Model Engineer 8.04.2022

THE ORIGINAL MAGAZINE FOR MODEL ENGINEERS ❖❖ Vol. 228 No. 4688 • 8 - 21 April 2022 Join our online community www.model-engineer.co.uk COVER FEATURE Rob Roy Rally QR Codes Stainless Steel Boilers What Can Go Wrong? ENGINEERING GROUP We Visit Westland £4.95



516 Published by MyTimeMedia Ltd. 510 Suite 6G, Eden House, Enterprise Way, Vol.228 No.4688 8 -21 April 2022 Edenbridge, Kent TN8 6HF www.model-engineer.co.uk 488 SMOKE RINGS 510 AN ASTRONOMICAL BRACKET CLOCK SUBSCRIPTIONS News, views and comment on the world of model engineering. Adrian Garner makes a bracket clock inspired UK - New, Renewals & Enquiries by Tompion and Banger’s regulator of 1708. Tel: 0344 243 9023 489 LNER B1 LOCOMOTIVE 513 MODERN BOILER Email: [email protected] Doug Hewson presents a true to scale CONSTRUCTION METHODS USA & CANADA - New, Renewals & Enquiries 5 inch model of Thompson’s B1. FOR THE MODEL ENGINEER Tel: (001)-866-647-9191 492 ROB ROY RALLY REPORT Luker suggests that it is worth exploring REST OF WORLD - New, Renewals & Enquiries modern methods for making boilers. Rex Hanman reports from Bromsgrove on a Tel: +44 1604 828 748 very enjoyable rally for Rob Roy locomotives. 516 WE VISIT THE WESTLAND Email: [email protected] & YEOVIL DISTRICT MODEL 494 GETTING IT RIGHT ENGINEERING SOCIETY CURRENT AND BACK ISSUES Rhys Owen says choosing the right tool John Arrowsmith rides one of the longest Tel: 01795 662976 for the job is vital when it comes to raised track back straights in the country. Website: www.mags-uk.com making accurate measurements. 520 A MINIATURE OSCILLATING EDITORIAL 498 A 7¼ INCH GAUGE STEAM ENGINE DRIVING TRUCK Editor: Martin R Evans Hotspur presents a three-cylinder, Tel: +44 (0)7710 192953 Tim Coles builds a two-seater driving truck reversible, oscillating steam engine. Email: [email protected] with an authentic prototypical look. Assistant Editor: Diane Carney 524 GIVE YOUR ARTICLES A Club News Editor: Geoff Theasby 502 A GEARED TRANSMISSION BOOST WITH QR CODES! FOR WESTBURY’S PRODUCTION ROAD ROLLER Luís Trincão explains how QR codes can provide a short cut to further content. Designer: Yvette Green Ted Hansen updates Westbury’s design Illustrator: Grahame Chambers for the Aveling road roller with something 527 THE LITTLE DEMON Retouching Manager: Brian Vickers closer to the prototype. SUPERCHARGED V8 Ad Production: Andy Tompkins 506 FLYING SCOTSMAN Mick Knights builds a V8 internal ADVERTISING IN 5 INCH GAUGE combustion engine. Advertising Sales Executive: Angela Price Peter Seymour-Howell builds a highly 530 CLUB NEWS Email: [email protected] detailed Scotsman based on Don Young’s drawings. Geoff Theasby compiles the latest from MARKETING & SUBSCRIPTIONS model engineering clubs around the world. Subscription Manager: THE ORIGINAL MAGAZINE FOR MODEL ENGINEERS Beth Ashby ❖❖ MANAGEMENT Vol. 228 No. 4688 • 8 - 21 April 2022 Group Advertising Manager: Rhona Bolger Join our online community www.model-engineer.co.uk Email: [email protected] Chief Executive: Owen Davies COVER FEATURE © MyTimeMedia Ltd. 2022 Rob Roy Rally All rights reserved ISSN 0026-7325 The Publisher’s written consent must be obtained before any part of this publication may be reproduced in any form whatsoever, including photocopiers, and information retrieval systems. All reasonable care is taken in the preparation of the magazine contents, but the publishers cannot be held legally responsible for errors in the contents of this magazine or for any loss however arising from such errors, including loss resulting from negligence of our staff. Reliance placed upon the contents of this magazine is at reader’s own risk. Model Engineer, ISSN 0026 - 7325 (USPS 24828) is published fortnightly by MyTime Media Ltd, Suite 25S, Eden House, Enterprise Way, Edenbridge, Kent, TN8 6HF, UK. The US annual subscription price is 136USD. Airfreight and mailing in the USA by agent named World Container Inc, 150-15, 183rd Street, Jamaica, NY 11413, USA. Periodicals postage paid at Brooklyn, NY 11256. US Postmaster: Send address changes to Model Engineer, World Container Inc, 150-15, 183rd Street, Jamaica, NY 11413, USA. Subscription records are maintained at DSB.net Ltd, 3 Queensbridge, The Lakes, Northampton, NN4 5DT, UK. Air Business Ltd is acting as our mailing agent. http://www.facebook.com/modelengineersworkshop http://twitter.com/ modelengineers QR Codes Stainless ON THE COVER... Steel Boilers A line-up of Rob Roy locomotives at Bromsgrove’s What Can Go Wrong? 2021 rally (photo: Rex Hanman). We Visit Westland ENGINEERING GROUP £4.95 26/03/2022 07:41 481 Front Cover 4688.indd 481 www.model-engineer.co.uk 483





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MARTIN Men’s Sheds chat. There are Men’s Sheds will not be relevant to the EVANS all over the country and the list vote. (This keeps counting Editor Before the covid pandemic is growing so there is almost the votes simple for me.) brought everything to a certain to be one near you. Alternatively, if you don’t have DIANE access to email, you can write CARNEY shuddering halt I used to Bradford Cup to me with your vote. In the Assistant attend an evening class, event of a tie the editor will Editor held at a local school on The nominations for the have the casting vote. Friday evenings. Moves Bradford Cup are now in and YVETTE to revive the class it’s time to start voting! The The result will be announced GREEN have proved fruitless, Cup is awarded to the best in June. Designer sadly, with the school article or series in Model no longer prepared to Engineer during the year 2021. Rob Roy Rally Martin Evans can be accommodate us. I have We have had five nominations, contacted on the mobile no idea why, as no reason as follows: In this issue, Rex Hanman number or email below was given. That leaves looks back to last year’s Rob and would be delighted to • Steam Turbines Roy Rally and looks forward receive your contributions, a small group of rather Mike Tilby to this year’s, which will in the form of items of disappointed model engineers. be held at the Bromsgrove correspondence, comment The class was as much about • Steam Engines club on 17th September. For or articles. coffee, biscuits and a chat as it Ron Fitzgerald information on how to enter 07710-192953 was about making progress on please contact Rex on 01980- [email protected] our latest projects and is much • Barclay Tanks 846815 or hanmanr@yahoo. missed. Many model engineers Terence Holland com. For more information about the club, including must find themselves in similar • Flying Scotsman how to find it, please see the situations. This is one of the Peter Seymour-Howell Bromsgrove club website many casualties, I suppose, of (www.bromsgrovesme.co.uk). covid-19. • Bolton Tram Ashley Best Club Diary Fortunately, there is an alternative to evening Please register your vote with Yes – the Diary is back! classes. The ‘Men’s Sheds’ me before the 15th May – one However, its usefulness is organisation (menssheds.org. vote of course per reader. The limited by the amount of uk) is a growing movement to simplest way of doing this is information it contains. So – establish places all over the by email. In that case please Club Secretaries – you know country where men (but not start the subject line with what to do… exclusively men, of course) can ‘Bradford Cup’ and follow that meet to pursue their craft and with the name of the article. DIY activities along with the Any content in the message very important tea break and Club Diary 23 Southport MEC. 8 North Wilts MES. Small Gauges Day, Victoria Public Running, Coate Water April Park 10:00–16:00. Country Park, Swindon Contact: Gwen Baguley, 11:00–17:00. Contact: 9 York Model Engineers. gwenandderrick@ Ken Parker, 07710 515507 Evening Talk – 19:00. yahoo.co.uk 15 North Wilts MES. Contact: Bob Polley: 24 North Wilts MES. Public Running, Coate Water 01653 618324 Public Running, Coate Water Country Park, Swindon 10 North Wilts MES. Country Park, Swindon 11:00–17:00. Contact: Public Running, Coate Water 11:00–17:00. Contact: Ken Parker, 07710 515507 Country Park, Swindon Ken Parker, 07710 515507 22 Bradford MES. 11:00–17:00. Contact: Running Day, Northcliff Ken Parker, 07710 515507 May Railway 13:30–16:00. 16 Bradford MES. Contact: Russ Coppin, Easter Bunny 2022, Northcliff 1/2 North Wilts MES. 07815 048999 Railway 12:30-15:00. Contact: Public Running, Coate Water 22 North Wilts MES. Russ Coppin, 07815 048999 Country Park, Swindon Public Running, Coate Water 17/18 North Wilts MES. Public 11:00–17:00. Contact: Country Park, Swindon Running, Coate Water Country Ken Parker, 07710 515507 11:00–17:00. Contact: Park, Swindon 11:00–17:00. 4 Bradford MES. Ken Parker, 07710 515507 Contact: Ken Parker, May Meeting - Spring Auction, 22 Southport MEC. 07710 515507 Saltaire Methodist Church Diesel Day, Victoria 17 York Model Engineers. 19:30. Contact: Russ Coppin, Park 10:00–16:00. Easter Steaming and Family 07815 048999 Contact: Gwen Baguley, Fun Day. Contact: Bob Polley: 7 York Model Engineers. [email protected] 01653 618324 Evening Talk – 19:00. Contact: Bob Polley: 01653 618324 488 Model Engineer 8 April 2022

LNER B1 Locomotive PART 4 - HORNS, WHEELS AND AXLES Doug Now we have got the 19 Hewson underframe completed presents an we can carry on adding Horns and axle box. authentic 5 inch gauge several other components to version of Thompson’s it. I think it would be as well if most successful we put the horn blocks on first locomotive. of all. They come as gunmetal castings so they will need Continued from p.391 machining in the usual way. M.E. 4686, 11 March 2022 They should be bolted on with fitted bolts. However, in our case I do not think that is worth bothering with such things as it is only a tender and, in any event, you need to think about the flexibility of the tender rather than such precision. www.model-engineer.co.uk >> 489

20 21 22 Wheel sets. Assorted suspension parts. (Photo by Alistair Bootland) Intermediate buffers. The main thing is to the tender wheels and photo number otherwise it will be 16swg plate and a piece of ⁄11 16 21 shows all the bits and wrong. They can all be made inch bar which can be silver machine the axle box so that pieces for the suspension plus from steel bar or plate. The soldered together. I didn’t it is a very good fit in the a draw hook and also there are buffer head is just a plain think I had any photographs horns. The side cheeks of a couple of the horn keeps and piece of ⁄9 16 inch round bar of the intermediate buffers on this little heap is one of the with the end slightly rounded the boxes need to be slightly but then, just like a bad penny, barrel shaped so that the axle box top plates. and drilled out with a ⅜ inch one turned up so this is shown boxes will tilt by at least ⁄3 16 We need to have a word clearance drill so that a ⅜ inch in photo 22 - so there we are, inch and you shouldn’t have spring will just slide in nicely. all complete. When fitting the any problems with the wheels about the intermediate buffers. The end needs tapping 5BA tender draw hook, I always locking up in the horns. On No tenders had these on until use a couple of ½ inch tap photo 19 I have shown a good 61040 Roedeer, so I would to take the ⅛ inch spindle 1⅝ washers as shock absorbers suggest you don’t put any inches long. so I would suggest that you view of the horns and an axle on your tender unless your do the same. box but I have not got any locomotive is above that The housing needs making decent photographs of the in two parts using a piece of horn keeps. However, it is only a small machining job from ¼ x ⅛ inch bar. They are fixed on with 8BA bolts. Now, just remember that they should have 1½ threads showing on the outside so I don’t want to see anything fixed on with set screws! The horn blocks are also fitted with 8BA bolts and the same applies to those. I used to judge the locomotives at one of the major exhibitions and these kinds of faults always used to bug me. I am trying to teach you how to build a prize-winning model! The wheels and axles come next, and castings should be available from Geoff Stait (G.S. Model Supplies) for these. Some time ago I made all the patterns for all your needs for the lost wax castings for all of the suspension for the LNER tenders and we sold lots of them in sets of both six and eight of course. Included in this lot are the spring hangers, shock absorbers (Spencer blocks), spring helpers and the spring hanger brackets. I have also made the axle box covers. The Steam Workshop also have all the bits and pieces to make up the screw couplings all cast in stainless steel. Photograph 20 shows a pair of 490 Model Engineer 8 April 2022

LNER B1 I used to judge the locomotives at one of the major exhibitions and these kinds of faults always used to bug me. I am trying to teach you how to build a prize-winning model! I just thought that I could have drawn it but I think you do with some photographs will get the idea). Photograph to go with this section and 24 shows the front view of the then a friend of mine came front drag box which looks very up trumps with several frame nice. Photograph 25 shows the stretchers for the 7¼ inch B1 rear view of the rear drag box he is building to my drawings which looks very well too. so now I can include some of those. Photograph 23 is the ●To be continued. front drag box (not quite as I 23 Front drag box. 24 Front view of the front drag box. 25 Rear view of the rear drag box. www.model-engineer.co.uk 491

Rob Roy Rally Report As with so many other 1 events, the 9th Rob Roy Rex gathering in 2020 was Chris and Yvonne Orchard in contemplative mood. Hanman a Covid casualty. All previous reports on meetings had taken place Also steaming round with One of the original aims last year’s rally and gives at the Andover club’s track ease was Rob Griffiths of the of the rallies was to have notice for this year’s. in Hampshire but a different host club (photo 2). It was Rob an opportunity for Rob Roy venue had been planned for a who was first on the track and owners and builders to get 2 change. With eased restrictions he had a second long run for together to exchange ideas and the outdoor nature of the most of the afternoon. Rob and offer help and advice. Rob Griffiths of the home club. event, the rally finally took place bought the engine on eBay and Regular readers of these at Bromsgrove in September after a few adjustments it is reports will have seen the 2021. Once again, after a day performing well. A fun fact is steady progress of Ian of heavy rain, the weather was that Rob has a brother called favourable. Roy! Claiming to be a novice, he Horsfield’s lovely example. seemed to be doing very well. Now completed, but as yet The author had a somewhat largely unpainted, Ian had been late arrival at the Bromsgrove 4 unsuccessful when steaming track as a result of solving it. Under the watchful eye of a heinous murder that took Desperate measures. The author tries to Chris and one or two similarly place on the Bluebell Railway clear the blocked blower. experienced drivers, Ian the night before (a highly recommended evening if you completed his first lap. From like ‘Murder Mysteries’). Loyal then on there was no stopping attendee Chris Orchard was him (photo 3)! already whizzing round the track with ease. Chris and The author’s day wasn’t Yvonne had travelled from quite as successful. A Somerset for the day (photo 1). stubbornly blocked blower Bromsgrove is set at the foot pipe defied all attempts to of the famous Lickey incline get ‘off shed’. All attempts to of 2 miles at 1 in 37.7 on the rectify the problem failed. The mainline between Gloucester and Birmingham. It is only rather undignified upending appropriate that the local club of the entire locomotive to should have its own version gain access caused a few in miniature. There had been comments (photo 4)! some concern that a Rob Roy would fail to climb it but Chris At first sight, I thought Ian was banishing all doubts. had started to build a second 3 Ian Horsfield flies past in a blur after completing his first ever successful lap. 492 Model Engineer 8 April 2022

ROB ROY engine but the very nicely supported the day (photos 6 5 built chassis belonged to Phil and 7). Hale from near Chester (photo Phil Hale’s very nice chassis. 5). Still a long way to go but Thanks are owed to the Bromsgrove society for he will surely follow Ian’s hosting the event at their lovely footsteps and end up with a site, which has a beautifully first-class example. It’s nice to smooth track. This year’s event see the next generation of the will be held on 17th September clan coming along well. 2022 at Bromsgrove Society of Model Engineering. Contact When Ian began his build, the club had no Rob Roys. Rex Hanman 01980-846815 or [email protected] or They now have six! Locals Bromsgrove MES. Alan Harris, David Anderson, Gerry Annett, and Phil Carey all ME 6 The traditional line up, with the author’s engine on the running line after a failed attempt to get off shed (the author, Phil Hale, Alan Harris, David Anderson, Chris Orchard, Ian Horsfield, Phil Carey, and Rob Griffiths). 7 Final curtain call for the participants. 493 www.model-engineer.co.uk

Getting It Right PART2 Rhys Owen Verifying squareness downwards and place against it and these are discussed looks at a set square that is standing on below. ways of The fact that a triangle with the machine’s table. A variation achieving accuracy with sides in the ratio of 3:4:5 was of this method is the use of a Straightness and flatness a variety of measuring a right-angled triangle was cylinder square, of which there instruments. well known in the Ancient are various types, some having The straightness of a rule can World. Pythagoras’ theorem a magnetic base. Effectively be checked by drawing a line Continued from p.465 was proved by Ancient Greek this is a precision ground between two points on a plane M.E. 4687, 25 March 2022 mathematicians who also cylinder whose end or base is then either flipping the rule showed that a right-angle at right angles to the body. over or turning it through 180 could be constructed using a degrees and drawing another ruler and compass. Yet another method is to set line between the same two up a dial test indicator. The points. If these two lines do not A precision set square may DTI is set up on an arm (e.g. deviate from each other, then be used to check that a vertical the DTI holder in a wobbler the rule really is a straight edge. milling machine’s table is truly set) that is held in the spindle However, the two points at right-angles to the machine’s chuck. When the spindle is mentioned above need to be spindle. Vertical milling rotated the DTI may be used to on a flat surface. Flat surfaces machines usually have special check the distance of the end are important for surface surfaces milled in the head of the arm from the table (or plates, machine beds, making casting. A precision set square from precision blocks resting joints without gaskets and may be placed on the table on the table) at different making steam-tight regulator and against these surfaces to positions. valves. Creating a master flat check the right-angle. surface requires a special Squareness can also be technique. Another method of doing checked using optical methods the above is to feed the quill DIAL TEST INDICATORS Fig 7 DTI with small cosine error. The original dial test indicator was Fig 8 the dotted red line) and moves to the new invented in 1883 by an American position (shown as a full red line). watchmaker named John Logan whose DTI with large cosine error. device basically consisted of a plunger Here the straight line between the two connected to a drum by a watch chain, the lever rather than a change of distance. For lever tip positions is at a small angle to the movement of the drum moving a needle small angle movements the arc through displacement of the red line, so that the on a dial. Logan’s patent was taken over which the tip of the lever travels can be error that arises - because the line between some years later by another watchmaker approximated by a straight line. Figure the two lever tip positions is at a slight called Frank Randall, who, together with 7 shows the situation where the lever a man named Francis Strickney, started starts roughly parallel with the surface to to manufacture the devices for industrial be measured (original position shown as use. These devices appear to have been of the plunger type in which the dial shows the distance by which a plunger is pushed inwards. Another type of dial test indicator is the lever arm type in which the dial shows the movement of a small lever arm. The end of this arm is shaped somewhat like a pear, the purpose of this being to minimise cosine error when the device is used to measure distances. Indeed, although both types of DTI can be used to measure displacements, when the lever arm type DTI is so used it is important to be aware of the effect of the angularity of the arm on the reading. Effectively, the lever arm type DTI measures a change in the angle of the 494 Model Engineer 8 April 2022

ACCURACY Gravitational attraction Fig 13 on the earth is directed towards its centroid so that Using a ‘toolmaker’s chair’. the directions of the force of gravity at different points of the earth’s surface are not parallel. It is thus not possible for a large surface such as the bed of a very long machine tool to be both flat and level (in the sense that a precision spirit level shows it to be at right angles (orthogonal) to the direction of gravitational attraction at the extreme ends of the surface). Determining deviation Often detecting deviation from a norm or datum is more important than establishing an absolute measured value. Detecting deviation can be done by various means and examples include: • Using engineer’s blue (or a similar coloured material) to find the high spots of a plate when offering it up to another flat surface (such as a master surface plate). • Using engineer’s blue when angle relative to the displacement - is Note that only for small angles of However, the most important use of the very small. movement of the lever arm can the distance lever-type DTI is not measuring distance of the arc through which its tip travels be but indicating variation in distance. For When the line between the two lever tip approximated as a straight line. example, although a round bar may positions is at a large angle relative to the be centred in a four jaw chuck using a displacement then the cosine error becomes Ultimately, the DTI registers angular surface gauge, a more advanced method significant. In fig 8 the true displacement is movement rather than distance. The dial of of doing so is to use a lever arm type DTI shown as a red dotted line while the lever a DTI can usually be turned to a convenient on a magnetic stand to determine which arm tip’s movement distance is shown as a position (e.g. with the needle opposite the of the chuck’s jaws must be moved to black dotted line. The location of angle θ is figure ‘0’). centre the bar on the axis of the chuck’s shown in green. rotation. 10 If θ is the angle subtended by the tip A DTI can also be used to ensure that movement distance relative to the true the spindle of a milling or drilling machine displacement distance, then: is concentric with an existing hole or with a toolmaker’s button (for this task a DTI tip movement = true displacement distance with two dials can be used). cos θ On a milling machine a DTI can be used against a parallel held in the jaws of a vice Where θ is 10 degrees, then Cos 10 to check that the jaw faces are parallel to degrees is 0.9848 so that the error is just the direction of the milling machine table’s over 1.5%. traverse. Photograph 10 shows a lever arm However, when θ is 45 degrees, then Cos DTI being used to check the alignment of a 45 degrees is 0.7071 so that the error is just milling machine vice. over 41.4%. The range of the lever type dial test Note that this is not related to the amount indicator is rather limited and it is of angular movement of the lever but rather important not to be fooled into thinking, to the orientation of the DTI relative to say, that a vice is well-aligned when in fact the measurement. So, to measure distance the DTI has reached the limit of the lever’s accurately, account must be taken of the travel! angle at which the DTI is orientated to the displacement to be measured. Checking vice alignment using a DTI. >> www.model-engineer.co.uk 495

SURFACE PLATES Fig 9 The frequency of a wave is the number AND OPTICAL FLATS of times that it repeats a cycle in a given A typical sine time period. This value is expressed in The traditional method of producing a function wave form. Hertz (cycles per second). flat surface is by hand-scraping. This The wavelength λ is the distance that requires the selection of a plate that is interference of a coherent light waves – in the wavefront travels in one cycle (in the already reasonably flat to begin with. fact the ultimate light source is the same but, above case along the horizontal axis). We A reference flat surface is covered with in some way, the light is split and then, after can think of this as the distance that a marking substance such as engineer’s blue taking slightly different paths, the streams of person would travel in two strides (that is, and the plate is placed on this reference light are recombined. The method requires to get back to the original position of the surface and removed. Some of the marking the use of an optical flat, that is, a plate of feet). If the speed of the wavefront is C (= substance will adhere to the high spots on glass that has been ground to a high degree celerity) then: the plate and these are removed using a of flatness. The surface that is to be checked scraper. The process is repeated until the must reflect light to a certain degree. The C = ƒλ flat surface exhibits a consistent pattern of light source should be monochromatic, that scraper marks over its whole surface. is, of one colour and thus, of one wavelength. For orange monochromatic light the wavelength is of the order of 600nm, that However, if no reference surface is The figures below should help explain is 600 nanometres or 600 billionths of a available then it is necessary to resort what happens but it is important to be metre (the frequency is around 5 x 1014 to the three plate method of creating aware that the dotted lines represent light Hz). Inserting these values into the above a flat surface. Although this method is wave rays that have a certain breadth. formula gives 300,000,000 metres per sometimes attributed to Whitworth, who What this means is that the light waves second, which is the speed of light. once worked in Maudslay’s workshop, it is represented by the two lines leaving the believed that, in fact, Maudslay not only top of the optical flat after reflection, In fig 10 it may be seen that two paths pioneered the routine use of the surface respectively, from the internal bottom face of light are reflected; one path a partial plate in an engineering workshop but also of the optical flat and from the surface that reflection of the incoming light from the the generation of surface plates by the is being checked in fact mingle together bottom surface of the optical flat and the three plate method. and this mingling has certain effects. These effects derive from the fact that the light In simple terms, if there are three wave consists of periodic repetitions of surfaces A, B and C, then the only way any peaks and troughs that can be represented two of these surfaces can meet with no by a sine function (fig 9). spaces remaining in between them is if all three surfaces are flat. If surface B is scraped against surface A so that they meet each other with no spaces in between, then there is the possibility that, say, A is convex and B is concave. If surface C is scraped against surface A so that it also meets surface A with no gaps then surface C will also be concave. If surface B and surface C are then offered up to each other then, both being concave, their surfaces will not meet each other with no spaces in between. The only way any two of the three surfaces will meet each other with no spaces in between is if all three are perfectly flat. One way of checking that a surface is flat is based on the phenomenon of ‘Newton’s Rings’ as discovered by Sir Isaac Newton when he studied optics. Newton’s rings are caused by constructive and destructive scraping a white metal Finding an edge first, indicating that the metal wrigglers) can be used to bearing so that it will conform is about to be cut (I was once determine when the milling to the shape of a journal. One of the problems told that a layer of marking machine spindle reaches • Using a surface gauge or dial encountered in the machine a given distance from the test indicator to determine fluid may be used in much the edge. However, it seems that deviation from the centre shop is that of finding an same way, but I have never wobblers work because of (‘run out’) when setting up edge, i.e. determining the used this method). Once the the friction between the tip of work in a four jaw chuck. relation between a milling relationship between the edge the wobbler and the surface • Using a dial test indicator to cutter and the edge of a part of the item and the spindle is of the edge with which it determine whether a milling that is to be machined. Pieces known then some sums may comes into contact so there machine’s vice is really set of thin paper (traditionally the be done to determine where is an element of judgement parallel to the table axis. paper used for hand-rolling to start machining. This is involved because once the cigarettes) can be stuck onto much easier if a digital read wobbler starts to move across • Using an optical flat to a surface so that, when the then the spindle has already determine flatness. cutter touches the paper, out is fitted to the machine. pieces of paper swarf appear Wobblers (also known as 496 Model Engineer 8 April 2022

other path a reflection of the remaining Fig 10 ACCURACY light from the top of the surface to be Multiple checked. Since both paths emanate from reflections. the same source they are coherent but Waves cancel each other out and the the light in the latter path must travel a light disappears. little further (in fact the length of the two legs of the ‘V’ shaped additional distance. Although shown as lines, the wavefronts of these paths in fact mingle. If the additional distance is an exact multiple of the wavelength then the wavefronts coincide and the light is intensified (fig 11). On the other hand, if the difference in distances is an exact multiple of the wavelengths plus half a wavelength then the waves cancel each other out and the light disappears (fig 12). Inspection and interpretation of the pattern of lines that can be seen when the light source is applied allows the flatness of the surface that is being checked to be compared with that of the optical flat. This use of constructive and destructive interference of light waves to measure very small distances is known as interferometry. Fig 11 Wavefronts coincide and Fig 12 the light is intensified. passed the ‘critical point’ edge finder and the Moore edge. Figure 13 shows the is important to ensure that (albeit, in skilled hands, by an edge finder. Essentially this principle. all surfaces are scrupulously type of edge finder looks like clean. infinitesimal amount). an inverted chair. The back The edge finder is very Electronic edge finders are of the ‘chair’ consists of a carefully machined so that The position of the machine the two horns at the top are work table relative to the also available. When the probe flat surface with magnets exactly the same distance machine spindle is carefully embedded in it. This flat from the projection upwards adjusted using a lever-type dial of such an edge finder touches surface is held on the edge of the bottom vertical surface. test indicator so that the horns the material then a circuit in question by the magnets is created that lights up an (clearly the edge must attract Material is removed from the of the edge finder are exactly indicator. these magnets). Above the corner of the ‘chair back’ (as the same distance from the shown in the diagram above) line projected downwards from Another, arguably more flat surface are two straight the spindle axis. A number accurate, method is the use edges that are equidistant to ensure that the edge finder of Youtube videos show of the ‘toolmaker’s chair’ edge from the centreline of the sits accurately on the corner toolmaker’s chairs in use. of the work piece. Clearly, it finder. These come in two ●To be continued. styles: the Pratt and Whitney www.model-engineer.co.uk 497

A 7¼ Inch Gauge Driving Truck PART4 Fig 17 Tim Coles constructs a driving truck built for two, in true prototypical style. Continued from p.445 M.E. 4687, 25 March 2022 Body and seat box box. Unfortunately, I settled and seat box were assembled for ordinary building grade using white PVA glue, with The body of the truck is made plywood and, despite careful ad hoc jigging to try and get from half-inch thick plywood. flat storage, the parts warped around the warping of some I got our local chippy to cut quite badly. In future, I will use parts. Note how the floor up an eight-foot by four-foot high quality marine plywood, panel has strips of three- sheet to produce the base, despite the extra cost. quarter by half inch hardwood sides and ends of the body, glued along the edge. The plus a set of parts for the seat I scribed the side and end strips are ¼ inch shorter than panels to simulate the planks the floor panel to register of the full-size wagon, using against the buffer beams. The a piece of steel rod suitably wagon body is then located pointed at one end. The body Marking out and scribing the planks on Assembling the wagon body with PVA glue using the end panels as spacers! In this view the wagon body side. A long steel rule the hardwood strips already glued on the edge of the floor panel can just be seen. was clamped in place for each scribe line and a pointed bit of steel rod was dragged along the rule. The end result looks quite like the individual planks of the full size. 498 Model Engineer 8 April 2022

DRIVING TRUCK Fig 18 Trial fitting of the wagon body onto the chassis. This view shows how the side Here a water cut blank body corner plate is being bent through 90 degrees, panel meets the floor panel, with the hardwood strips glued onto the underside along a groove water cut for the purpose. Two bits of angle steel clamped in the big vice held the blank whilst wielding the hide mallet. of the floor panel. The wagon body then fits neatly between the buffer beams, located by the hardwood strips. The completed wagon body in place on the chassis. Note the ½ inch square hardwood Trial fitting of the seat box into the wagon body. This photo strips bolted onto the end panel and dropping down to the bottom edge of the buffer also shows how the foot boards look when fitted. beam. The three captive bolts for the footboards can also be seen in this shot. >> www.model-engineer.co.uk 499

laterally by these strips, Fig 19 against the upstanding parts of the bogie stretcher angle brackets and longitudinally by the buffer beams. Note also the ½ inch square hardwood verticals which are bolted to the end panels of the body, also serving to locate the body structure over the buffer beams. The water cut strapping was fixed to the woodwork using a large number of countersunk 6BA screws, with the nuts on the outside, as in the prototype brick wagon. Steel strip was fixed along the top edge of the wagon body panels, using small countersunk screws. The corner plates were water cut, with a groove water cut along the bend line. I don’t have a bending brake, but hammering Fig 20 Detail shot of the foot board fixing wing nut assembly. The M10 bolt Detail shot of the is captive, fitted with a threaded M10 boss and helps hold the bogie foot board fixing stretcher onto the channel longeron. bracket, from below. The six Fig 21 40 x 40 x 3mm angle brackets are 500 a bit flimsy but have held up in operation so far. Model Engineer 8 April 2022

DRIVING TRUCK Fig 22 the plate over to 90 degrees in Fig 23 the vice worked perfectly well. The seat box was assembled much like the body, with a big hole in the top for the water filler cap. Friend Steve Hodgetts welded up the coal ‘bunker’ from mild steel sheet and this fits snugly into the space in front of the seat box. My wife Caroline upholstered the lid of the seat box, this being removable to access the water tank filler cap. The footrests are just strips of ply with three steel hangers, which are easily attached to the captive bolts on the chassis with wing nuts. ●To be continued. NEXT TIME 501 We install the water tank. www.model-engineer.co.uk

A Geared Transmission for Westbury’s Road Roller PART4 The intermediate gears Fig 13 Ted Hansen The intermediate gear set replaces consists of the countershaft Westbury’s (fig 11) and the idler gear (figs original with a more 12 and 13). The countershaft prototypical gearbox. is made up of four gears silver soldered to a central Continued from p.441 sleeve (photos 16 and 17). M.E. 4687, 25 March 2022 Apply silver solder only to the outside edges of the gears - Fig 12 silver solder running into the teeth of the smaller gears where they butt against the larger ones would be very difficult to remove. The countershaft gear assembly rotates on a ¼ inch steel shaft which passes though the case. It is retained in the case by #4-40 screws with washers capping each end. The idler gear. The idler gear spacing. 16 The idler gear mounts on a shoulder bolt against the right- hand side of the case. The shoulder bolt for mounting the idler gear is a simple turning exercise and can be made as a slotted head screw if you haven’t any hex stock and don’t want to go to the trouble of making a hex head. The thread can be screw cut in the lathe or just put on with a tap. 17 The assembled countershaft. The countershaft gears and shaft. 502 Model Engineer 8 April 2022

GEARBOX Fig 11 Fig 14 Parts for the countershaft. The output shaft exploded. >> The output shaft assembly 503 The countershaft gears mesh with the two large gears which freely rotate on the output shaft (figs 14 to 16). Between the two gears is the shift collar with four drive pins. This collar can be slid left or right to engage either of the gears and transmit the power to the spline on the output shaft. Because there is a gear on either side of the spline and the diameter of the spline is larger than the bore of the gears, the shaft cannot be inserted into www.model-engineer.co.uk

Fig 15 The output shaft and final drive gears. Fig 16 The output shaft, spline and bushing. Model Engineer 8 April 2022 504

18 Fig 17 GEARBOX The output shaft. Note the fine-tooth The shift collar. spline instead of the easier four spline shaft described here. The shifter fork. place by passing it though the Fig 18 19 Trimming the gears. The shaft is therefore inside profile of made in two parts so that each are press fitted into the shift the shifter fork. can be inserted from the side. collar and the holes in the gear The spline is integral to the left- are slightly larger than the pins 505 hand shaft while the right-hand to ensure smooth operation. shaft is a hollow sleeve over a central stud. ●To be continued. Photograph 18 shows a fine NEXT TIME spline on the output shaft for the speed change selector. We fit the chain drive. This was quite difficult to make because my shop-made broach would not cut the internal spline in steel so a brass insert was needed for the shift collar. The simpler four tooth spline shown in the drawings should be much easier to construct. If you do not have access to a broach to form the internal spline, the slots can be made by hand filing or by traversing the lathe carriage with a suitably shaped tool in a boring bar. The external splines on the shaft could also be made by traversing the lathe carriage with a suitable cutter to ‘plane’ away the excess metal. An alternative method would be to braze four keys into slots in the shaft. The large radius on the shifter and clutch forks (figs 17 and 18) can be finished in the lathe with the fork mounted on a faceplate or by using a boring head in a milling setup as shown in photo 19. The holes for the drive pins in the shift collar and the gears are best located using an indexing device to ensure accurate spacing since it is imperative that the pins engage the gears in any rotational position. The pins www.model-engineer.co.uk

Peter Seymour- Howell builds a fine, fully detailed model of Gresley’s iconic locomotive to Don Young’s drawings. Continued from p.435 M.E. 4687, 25 March 2022 PART 32 – CAB DETAILS: VENTILATOR, WINDOWS AND WASHOUT PLUGS Painting by Diane Carney. Flying Scotsman in 5 Inch Gauge 1. I cut four pieces of brass strip to make Ventilator the right-angled flange that an inner frame so that when assembled surrounds the hatch as part of within the opening it was a tight fit holding I decided I would make this the removable section itself but itself together. The plug is seen here a removable item. Firstly, it when looking into this deeper sitting lower than it will be in practice. The gives me a better view of I thought that the joint might parts were then placed on the hearth, held the manifold and the various be visible due to the flange square and silver soldered together. working valves associated needing to match the curvature with it and, secondly, it will of the roof and remain in shape allow more light into the cab over time. To avoid such an and thus help me to see more issue, I decided to permanently clearly the controls within. I had solder the right-angled flange originally thought about having surround directly to the roof. So, I needed to start by making 2. Next were the three pieces of the up a strong plug or outer frame outer frame. You can’t tell from this to fit into this aperture that angle but the end piece has already would also hold the ventilator been curved to match the roof after roof in place. first being annealed a little. 506 Model Engineer 8 April 2022

FLYING SCOTSMAN LEFT: 3. To attach to the roof I first tinned the parts and then sweated them in place. 5. The plug was then held in the machine 6. This picture shows the ventilator The two sides are held in place via clamps and lengths of rusty steel (to avoid getting vice and the two sides were milled down to just above the line, the cutter was hatch now fitted. For the curved section stuck). The curved section was then checked for fit and trimmed until it could slide moved in closer than required to the I annealed it first and shaped it by hand under the lengths of steel and be trapped in place. The job was then gently heated centre until it just touched the black using the wooden pattern used for the from below until I could see the solder moving and I added more solder around the marker. I did this by eye, the idea being roof and then tweaked to match the plug. This was then clamped in place and soft inside edge and corners for extra strength. RIGHT: 4. With the flange filed to height that I could then file down the sides to soldered together. Finally, the top was and the front trimmed to match the roof/spectacle plate I then fitted the plug and meet the angle of the arc. sanded until smooth. marked with a felt tip pen the area that needed to be removed for the ventilator roof to match the arc of the cab roof below. 7. The runners were made from four 8. Here’s the ventilator top showing the 9. Here we have the frame parts ready. 10. The inner frame is secured to the pieces of strip, the recesses for the covers in place. After drilling the holes The newly cut frames are thicker in side sheet by four bolts. section and the outside edge hasn’t hatches to slide in milled and fixing tabs for the little knobs to fit in I curved each shaped, and then silver soldered together. cover to match the ventilator roof. I been filed to size yet, I’ll do that once the The recesses and the corresponding area have to say that I’m very happy with the glass is fitted. I silver soldered a brass on the hatches will be kept free from paint resulting easy sliding action. strip on each of the thicker frames, as for smooth sliding. it’s this frame that will be the back of the window. The thinner frame will be against the spectacle plate and the glass will be between the two. The brass strip is what holds the window unit in place. Windows the front side window forever double glazed so to speak. Wooden Frames sliding open. For the spectacle These are slightly different in I made templates for the side windows I already had two size and also a little thinner Once the window frames and windows first. These were frames in brass laser cut by to keep the overall thickness glass had been cleaned, I just the basic outlines cut Malcolm at MEL but needed down to something that looks sanded down the frames for a in alloy to check for fit and another two slightly thinner to right but more importantly will better bond. The long process that the rear window slides sandwich the glass between fit in the space available. of covering the outside edges smoothly. I decided to fix the and so making a sealed unit, with a wooden veneer then forward window for simplicity began. The veneer itself is >> and neatness, as I don't want www.model-engineer.co.uk 507

11. Here is one window after being 12. Now I needed to make the frames for LEFT: 13. I then needed to form the frames. I think the picture shows what I did the wind deflectors. I found some brass roughly cut out ready for final sanding square section that was just right for well enough. I first measured where the cut needed to be, cut a ‘V’, folded and soft to profile using the belt sander. As this the frame itself. In this picture the brass soldered. I did this with a piece of glass sitting in the slot to keep the parts square involved curved lines I cut this out using square section has had a slot cut down a cutting disk in a Dremel. With the glass the middle along one side. I did this while soldering. With the first right-angle done I marked out the next ‘V’ (remembering using a Dremel disk cutter in the mill. I that the bottom is wider than the top)and repeated the process. Once finished these profiled to its final shape, it was then used this rather than a slit saw cutter frames will be polished and the joint will be virtually invisible. I then drilled the ends time to fix it to the brass frame. For this as I could feed the section through by of the frames to solder in a short length of brass rod (cut to length later). I then I have used a black RTV silicone which when cured will look very much like the hand while pushing up against a ‘stop’. machined some right-angle section into the brackets required. Before fitting, the I couldn’t do this using a slit saw as I’d corners where filed round and the mounting holes were drilled. I also machined a rubber seal on the full size. RTV is used semi-circle into the middle of the top bracket so that it was a snug fit up against the as it will stick with a strong bond to both need to fix the section down securely single bolt which is where the prototype holds the bracket. RIGHT: 14. This picture the brass frame and glass window, and it which isn’t easy when it’s only 2mm wide shows the two windows and the wind deflectors made before getting out Mr Sheen can withstand very high heat. It can also and so delicate, the Dremel disk worked if needed be easily cut away with a sharp well so I was happy. for a little polishing. The silicone that had squeezed out from between the frame and scalpel. glass was trimmed off with the scalpel once cured. 15. Here’s one of the deflectors 16. I started with the bottom of the 17. Here are all four side windows at now fitted to the cab. window, placing the inner edge just a stage ready for profiling the inner above the brass frame so that it overlaps shape of the frame. The frames shown of the 'iron on' type and is the glass, and then added further strips. here have all had their outside edges approximately 0.06 mm thick. Here, I am ironing the veneer on. This trimmed and sanded down so that the I chose mahogany for a couple iron is over 20 years old, from my days brass centre with the two veneers is all of reasons - it is very close to of radio controlled aircraft. This iron flat ready for the edges themselves to the required colour and it is was used for covering wooden frames in be covered. You can also see the copper also has very fine grain which template which will be used to mark out looks good enough in 'scale' ‘Solartex’ or ‘Solarfilm’ and was perfect the inner shape. This job requires a little terms. for this particular job. I set the temp for care as both sides must be the same or 300 degrees C. you’ll see the inner edge of the veneer through the glass. 18. This picture shows one of the windows with both edges covered and sanded down to blend in. The top and bottom are left uncovered as they are hidden in the runner slots. 508 Model Engineer 8 April 2022

F LY ICNhGaiSrC OT S M A N g. 1 photo 4 19. It was then time to tackle thpehdoelticoat5e job of cutting out the 20. I fabricated the wee handles for the rear windows. I made 21. Here are the side windows installed inner shape using the template shown earlier. I drew around these out of small right-angled brass soldered back to back to in the cab. An arm rest has been added the template using a pencil and then cut out the shape by hand form a ‘T’ - it was then just a case of cutting/filing to shape and to the opening rear window. using a new scalpel blade, in this case a number 11 blade. Of them gluing in place. Here’s a picture of one of the windows, note here is the alloy film that I have protected the glass with with varnish applied and the handle fitted.  when sanding down the face to blend in. 24. NoPwhwoe htaovgerthaepchov7er ■unit fitted. WThaesrehaoruetaPclouugpsplehooftloas6t The countersunk 14BA screws are temporary until I can get hold of some details to add, this time the two round heads to match the prototype. It may be that 16BA would be closer to washout plugs and their covers.  scale but that’s pushing my luck a little, The internal taper of the tapping through 2 mm of brass. They look big in this close-up but you can cover is 15 degrees and rather hardly see them when standing back. I’ll see what the round heads look like when than following the prototype, I have them before deciding if I need to turn the heads down a little or not. I also with the taper going all the way changed my mind about the position of the plug, as you can see! through, I have left a return 23. Here are the covers with their plugs. and centre drilled that to take There are two sets of plugs here as I a 4 mm thread. I have done changed my mind about the size and this as I wanted to include the decided that the bigger plugs were closer washout plug as it's visible on to the prototype. There’s a 4 mm nut on the prototype and having the the back to lock the plug in place to a return means I can make this depth that looks right to the eye. This part as a single contained unit won’t be seen when the loco is finished as it’s hidden in the deepest depths of Next Issuewiththeplugfittedtothecover 22. Here we have the two covers ready for the plugs. You can see the back return walls with their centre holes drilled but not tapped yet - at this stage I wasn’t sure what size threads the plugs the cab and the wooden flooring masks ●To be continued. would have. this area. No.315 LookLooouk otuftofrorytohue rMcaoypisysuoe,f MEW 315, helping you get etvheen mMoareyo2u0t 2of2yiosusruweo:rkshop: Ian Strickland makes a boring Bob Dodds explains how to make Roger Froud explains the table for a lathe. a versatile nger plate. properties and uses of ceramic balls. On Sale 22nd April

An Astronomical Bracket Clock PART26 Adrian This is the time to make Garner up the hardened steel makes a end cap which supports bracket clock showing the end of the vertical arbor. both mean and sidereal This is effectively an end stone time. and avoids the arbor shoulder bearing on the brass and Continued from p.460 generating unneeded friction. M.E. 4687, 25 March 2022 An end stone could be fitted but, as the arbor only turns once a year, a hardened steel plate is perfectly satisfactory. The end cap was made from a piece of gauge plate by drilling three 10BA clearance holes on the needed pitch circle diameter and sawing oversize. A temporary arbor was then made up to hold it whilst turning to size. After polishing, harden and leave glass hard. Fig 54 Tellurian base 1 Base: 3/16\" brass Ø7.0000 Bevel 0.0500 No.30 28t, 0.75 module, 124 Re-polish to a mirror finish 0.1250 0.2500 O.D. 0.908 (photo 124). Temporary arbor for machining the end cap. 0.1875 0.1250 2BA 1.0000 To mount the drive, mark 4BA 0.2188 out and drill a 1⁄8 inch diameter 0.700 dia. hole in the tellurian base at the position the vertical arbor 1.3750 should pass through. Position the tellurian base centrally on 5/16\" OD, 1/4\" A/F the top of the clock case and screw in position. Secure the clock frames in the case. Turn a point on the end of a 1⁄8 inch silver steel rod. Rest the beam to support this arbor roughly in position on the top of the clock 510 Model Engineer 8 April 2022

ASTRONOMICAL CLOCK plates and lower the silver steel 125 126 rod down through the tellurian base onto the beam. Check the rod is upright and mark the beam (photo 125). Remove the beam and mark where the hole should be drilled, that is aligned with the mark but halfway across the width of the beam. Drill the pivot hole and replace the beam and silver steel rod, this time with the point resting in the pivot hole to position the beam so that the rod is again upright. Mark where the beam is to be mounted on the clock plates. Mounting the beam requires ‘merely’ two tapped 10BA holes in the top of the plates. I just managed to drill these on my milling machine with the clock plates vertical and the head fully raised. With a jig it might be possible to drill and tap these by hand but I suggest finding a friend with a drill or mill with sufficient throat to ensure the holes are Checking the alignment of the vertical arbor. Upper support plate in place. square to the frames. Before opening up the 1⁄8 large hole will be covered by be mounted (photo 126). The industrial glass blowers (ref inch hole on the tellurian base the upper drive wheel. pillars between the cross 20). The size to fit my base and plate use this hole to mark The only comment on the beam and upper support plate tellurian was 185mm O.D. by out (depth) the position of vertical arbor is that the arbor should initially be made over 155mm height but do check the intermediate wheel stub length should be made a length (say ½ inch) so that the your clock before ordering. arbor’s tapped hole. Also use loose fit between the beam 50T wheel does not engage I engraved the tellurian base this hole to position and mount mounted on the clock and with the sidereal wheel. The in the lathe with fine lines the cock on the tellurian base cock mounted on the tellurian object at this stage is to showing 365 days and the plate with its centre line over base to allow for any variation position the support plate so months. At the same setting I the 1⁄8 inch hole. Drill the upper in registration of the clock, that the worm and wheel on also engraved lines indicating pivot hole. tellurian and case. The pivots the vertical arbor correctly the equinoxes as well as the The 1⁄8 inch hole in the are made correspondingly engage. Slide the assembly summer and winter solstices. tellurian should now be drilled longer than usual. along the clock plates until I had the names of the months and bored out to about 0.7 The upper support plate correct engagement is reached as well as the names of, and inch so that the wheel mating for the arbor connecting the and then mark, drill and tap the symbols for, the equinoxes and with the worm can be lowered sidereal wheel with the vertical 8BA holes in the clock plate. solstices hand engraved on into position on the arbor. The arbor to the tellurian can now Mount the support plate and the plate along with ‘Ecliptic check all is well. The pillars Plane’ and ‘Moon’s Orbital 127 can now be reduced in height Plane’ on the rings (ref 21). until a good mesh with the Ruth Anthony also excellently sidereal wheel is obtained engraved the cartouche. (photo 127). They can be held Assembly in a collet for turning. Take small cuts, say 0.005 inch, and Earlier notes described retest as correct engagement assembly of the clock. To is reached. The power transfer complete these for the needed is small so better to tellurian: be too loose than a grumbling fit. The wheel meshing with 1. Mount the two cross beams the worm can now be fixed in for the tellurian drive on the position. top of the clock plates. The The dome and engraving design uses 10BA holes for one beam and 8BA for the The dome to fit the tellurian other to ensure they go in was made to order by a very the correct position. The The pillars are adjusted to achieve a good mesh with the sidereal wheel. helpful firm of scientific and securing holes for upper >> www.model-engineer.co.uk 511

support pillars should face with 320 grit paper. This was 128 outwards from the center of done on a board on which the clock. a screw acted as a pivot Clock secured on the tellurian base plate. 2. The clock can now be for a wooden arm around positioned in its case by which the wet and dry paper • The hands were similarly hand and hot plate causing leaning the clock backwards was wrapped. Use plenty of treated but the heating was uneven bluing. When this and rotating to the upright water to prevent the paper mostly carried out on a hot occurred I reverted to using a position once inside. clogging. The cartouche and plate in a bluing machine tray with heated sand. 3. Add the upper and lower all the other engravings were based on the design • All brass surfaces of parts brackets that secure the treated similarly except the published in HJ (ref 22). I say behind the face were polished clock to the case. grain was kept straight on mostly as my success rate to 8000 grit before cleaning 4. Mount the tellurian base the cartouche. They were with the long hands was less in an ultrasonic tank with the plate on the top of the clock all silvered and to prevent than one hundred percent. L & R solutions mentioned together with the central oxidation were given a coat of Even the slightest curvature above. After drying all holes fixed arbor. Renaissance Wax. of the hand creates an air were pegged out. 5. Position the tellurian on the • The bought in spandrels insulation gap between the central arbor. Secure the were cleaned in Horolene and lTo be continued. fixed wheel to the central lacquered. arbor. Add the spigot and • All steel screws were REFERENCES intermediate wheel polished in stages starting 6. Mount the upper support with 600 grit and finishing 20. Suffolk Glass (UK) Ltd., Chilton Street, Clare, Sudbury, plate assembly linking the with 8000 grit and then Suffolk, CO10 8QG. sidereal wheel with the ultrasonically cleaned in L & tellurian vertical drive arbor R No. 677 Waterless Non- 21. [email protected] 7. Lower the tellurian vertical Ammoniated Clock Cleaner 22. Making a Bluing Box by Geoff Walker, Horological Journal, drive arbor into position followed by Watch Rinse. and secure the cock on the Before bluing they were August 2013, pp348-450. tellurian base plate (photo dipped in isopropyl alcohol 128). to remove any traces of oil from the rinse, left to air dry Polishing, filling, on kitchen paper and then silvering and bluing placed with cleaned tweezers into a clearing hole drilled in Unlike a skeleton clock where a strip of ⁄1 16 inch thick brass. all parts can be seen in detail, They were heated over a spirit a sense of proportion is burner before quenching in needed. I opted as follows: oil. They are dried in kitchen towel to remove most of the • The outer face of the clock oil, only a thin protective film was polished to 1000 grit being left. with the scratches vertical, washed in water and given 129 a light protective coat of Renaissance Wax to The finished tellurian. moderate oxidation. Once finished, it was only handled with gloves. • The inner matted part of the clock face was cleaned in Horolene to remove the oxidation since it was matted, rinsed in water and left to dry. Again, as for all other parts, once finished it was only handled with gloves. • The engravings on the chapter rings, cartouche etc. were filled with a mix of slow, rather than the rapid, setting Araldite and the powder called ‘Carbon Black’ used by artists. Unlike wax this type of filler does not weep. After leaving to fully set for a couple of days the chapter rings were cleaned up and given a circular grain 512 Model Engineer 8 April 2022

Modern Boiler Construction Methods for the Model EnginePAeRTr2 Luker The boiler data pack TIG welding copper 10 argues the case for For critical welds, which in My very first welded boiler TIG welded copper boiler 3.5g William. considering the adoption a boiler are all of them, each was copper TIG welded with of TIG welded stainless weld needs to be properly the bushes and tubes silver weld is normally done on all of steel boilers. described. This is called a soldered; I wanted an easy the joints with low hydrogen boiler build! That was a little stick welding used thereafter. Continued from p.383 Procedure Qualification Record 1.8 litre 3½ inch gauge boiler All weld preps. are properly M.E. 4686, 11 March 2022 (PQR) and typically includes (photo 10) and is still one of designed and checked prior to parameters like the amperage, my favourite locomotives to the builder closing the boiler. 11 take to the track. The welding Generally speaking, the plate gas flow, rod types and sizes procedure and methods are thickness and barrel thickness etc. Photographs of all of the very similar to the methods are far greater than code with weld preparations and general previously described with the the tubes expanded into the fabrication should be taken exception that copper needs tube plates. When the boiler is and added to the data pack to be preheated, typically to hydraulically pressure tested 400 degrees C. The model it is not uncommon to find with the material certificates builder might not have access very small leaks that show and other necessary to fancy temperature chalk up as sweating, typically on documentation to be reviewed or infrared thermometers so a tube joint. This is generally by the boiler inspector. Our a practical test is necessary; not a major concern and on poor boiler inspector gets a if you start welding and a the first or second steaming DVD with every weld prep., weld pool forms then the these weeping points sort material heat number, boiler temperature is correct. For themselves out. One of these design report and calculations the most part the boiler needs larger boilers worked every etc. but that’s how it should be. to be covered with a welding other week hauling hundreds blanket (non-flammable of passages for 15 years Weld samples of each weld insulation will work) to before the tubes started should be welded in the form prevent heat loss, especially leaking at the expanded joint. of a ‘V’-angle using the same if a smaller welder is used. The builder subsequently let For much smaller copper me know that when he gets weld prep. as in the PQR. welded boilers preheat is not around to it he’ll overhaul the Using a vice, the sample is necessary provided the current locomotive and check the bent in on itself; if there is no heat input is enough to form a boiler shell and firebox but evidence of cracking the weld weld pool (photo 11). from preliminary checks it is good. These samples should looks like only the tubes will be marked with the date and One warning with welding need to be replaced. copper - not all copper can be PQR number and submitted to TIG welded. It depends on the (and kept by) the club’s boiler way the plate is made, with inspector along with one or process-entrapped oxygen two welding rod stubs showing resulting in porosity the the material stamp. biggest issue. Here, welding test samples and bending will A tiny copper welded boiler showing weld seam. give a good indication if the >> plate is suitable for welding. Welding steel boilers I have personally never welded a ‘normal’ steel boiler simply because there is no cost or construction benefit for my size of boilers. The members of our club that do construct steel boilers (rather large boilers I might add) do so based on existing boiler codes. A fusion (TIG) root www.model-engineer.co.uk 513

TIG welding 12 13 dissimilar metals Dissimilar parent materials Example of an excellent weld. It is possible to weld dissimilar using nickel TIG welding. parent materials and I have was easier to weld and gave experimented with this critical components used in visible and some un-welded better results at the expense of personally and in industry. This industry. I actually didn’t believe ‘V’-preps on the other side thermal conductivity. is a field of study on its own them when they said it was not of the assembly, and they but as a general rule nickel is an automated welding process just looked wrong. After an Interpass and preheat an excellent filler rod for joining until they welded a sample annoying discussion with the temperature too low is a materials that are worlds piece for me. The close-up welder and foreman I picked common welding problem apart (photo 12). This could (photo 13) is of a root weld for up a grinder and cut through with copper, especially when be used for copper tubes to a multi-pass weld joint. one of the welds to show a MIG is used. The filler wire is steel tubeplates or stainless very dangerous poor weld melted and deposited onto to the bronzes for steam pipe Poor root penetration is one penetration condition. I was the base material but does applications. This is the ‘next of those scary welding defects subsequently chased out of not fuse properly (photo 15). level’ when it comes to welding the workshop because I had For welded copper boilers the and not something I would because it is very difficult to not gone through the in-house TIG amperage will just not be recommend on any pressure pick up with visual inspection. grinder training. Needless to enough to create the initial critical components but it is Even using NDT like Ultrasonic say, all those welds were back weld pool, so this failure is nice to know it can be done. ground and re-welded with less likely to happen in our Of course, brazing (or silver Testing (UT) sometimes full UT on 100% of the welds applications but it is possible soldering) is a more convenient misses the root gap. If the including weld prep. photos to weld copper with the and an easier dissimilar metal back-side of the joint is visible and measurements. The amperage too low if the base joining process. you can sometimes see the inspector on that job became metal preheat is too high. If the corner was colder than the very pedantic after that. copper filler bead is rounded Common welding failures without neat blending to the outside heat affected zone, The picture showing poor base material it’s likely the I had every intention of welding which is an indication that root penetration (photo 14) weld temperature was too low a few examples of common the welding has only taken is an AB1 filler rod joining and the weld strength is lower defects (I even had the TIG on the sides. If the ‘V’-prep is a copper anchor. This was than it should be. I’ve included torch in my hand and the development I did on cooling a picture of a good non-ferrous gloves and helmet on) but I incorrect (angle too acute) for elements that failed structurally weld with correct amperage, just could not bring myself the type of material and weld with a copper weld due to preheat and interpass to do it. Luckily for me I have joint then it’s unlikely the weld poor sidewall fusion. The AB1 temperatures for comparison a considerable library of (photo 16). pictures from inspections I will fill the prep. properly. I have done when I’m not doing inspected a granulation tank I Undercutting is less simulations. I actually enjoy had designed many years ago of a problem with boiler this part of my job far more with the back of the welds still than watching residuals on a computer screen. The best welding I have ever seen was done by Mongolians; the welds were neat, uniform and passed all of the rather intensive Non-Destructive Testing (NDT) which is necessary for some of the 14 15 Poor root penetration. Interpass temperature too low resulting in lack of fusion. 514 Model Engineer 8 April 2022

BOILERS construction because the 16 happens within a day or two 17 overall weld design has more so I never close the inner parts than enough factor of safety An example of a good non-ferrous weld. of the boiler the same day Undercutting on a very large lifting lug. and the overlap joint type is they are welded. This mode less likely to produce this type 18 of failure is highly unlikely 19 of weld defect. Nonetheless to occur with TIG welding it is something to look out for, TIG fusion welding to cover poor welding if the weld area is clean Start - stop welding defects. especially on stressed areas resulting in leaks when pressure tested. and the shielding gas is not the boiler inspector to check like stays. The example of ramping the current gradually contaminated. For steel boilers competency, as it should be. the lifting lug (photo 17) was at the beginning and end of the low hydrogen welding rods will The Australian code does a scary one I picked up on a weld runs. Alternatively, the prevent this but as a rule any require a rather stringent 20 ton lifting frame, which weld is started just outside the flux coated welding rods that welder qualification (AS1796 weld prep and the arc is drawn have stood for long periods in with a minimum of two years’ somehow passed official into the weld area. Photograph a damp environment should experience) but even there inspection. Undercutting is 19 shows one of my boilers be baked prior to use. The box an amateur can weld his own typical if the heat input is too around the outside of the fire typically has the temperature boiler under instruction from a high (at the edge of a joint door ring so corrosion is not and baking time on the side qualified person. the heat has less dissipation an issue (note the balancing of with a commercial oven more paths which is why this defect the weld to limit distortion). than adequate. ME often occurs there) or not If the welding amperage is In closing 20 enough filler rod is fed into the too high this can result in over- weld pool, which incidentally penetration with the top of The perception that you need Overpenetration on the inside of a weld. is how this defect is countered the weld smooth and mottled a fancy welding qualification at edges. instead of the correct wavy (or to use workshop slang ‘be a pattern (photo 20). The inside coded welder’) to weld properly Fusion welding to prevent of the weld will sometimes is a fallacy. The UK code leaking is one of those show a dark area where the does not require the welder shortcuts I sometimes allow weld has broken through the to be qualified but samples depending on the severity. base plate. This can result in do need to be submitted to If minor leaking is detected weld sensitization in stainless during the pressure test but or porosity with copper welds. the vessel is still structurally sound I would generally Cracking in welds is accept a small fusion weld something that can occur to close the leak, as long as due to thermal distortions or the immediate area is heated hydrogen contamination, to to get rid of any water. Back- name just two. As a general grinding and re-welding rule hydrogen cracking tends to move the problem due to thermal distortions, so a smaller fusion weld will limit the thermal input and subsequent failures. For our boilers this is sometimes a better option than full back grinding and re-welding, especially with the stainless steels, but each case needs to be considered based on its merit. The accompanying example of a pipe run with fusion runs to fix leaks was not accepted (photo 18). I bought the welder a soft drink and had a 30min chat about the weather, hobbies and sport, then asked him to redo the pipe run. It came out perfect second time. Stop - start welding inclusions is the initial arc strike at the beginning and end of a weld run. This is a minor defect causing weld sensitisation typically resulting in corrosion. If the welding machine has a sloping setting this can be eliminated by www.model-engineer.co.uk 515

A passenger’s eye view of the track as it passes the steaming bays. Detail of a point operation where the point is under the bridge. We Visit the Westland & Yeovil District Model Engineering Society John Following my visits to the A general view of part of the O gauge SM32 garden railway. Arrowsmith north Somerset clubs I heads south continued further south for housing and asked them to and suggested both clubs to Yeovil, to helicopter and went to the Westland leave. At about the same time should merge, which they did. country. & Yeovil District MES who another local club, the College He then spoke to Westland on are located at the Westland Engineering Club were asked to their behalf and not only did he 516 Leisure Centre right next to the vacate their site as well so now manage to arrange for another Westland helicopter factory in there were two organisations piece of unused land to be Yeovil. When I arrived, I was looking for a suitable piece of made available, he secured a met by chairman, Len White land. Fortunately, MP Paddy decent donation as well. The who showed me round. Len Ashdown became involved Westland and Yeovil District explained how the club has thrived despite problems over land acquisition. This club has been in existence since 1964 when 10 or 15 people, the majority of whom worked for Westland Helicopters, got together to form a model engineering club. They managed to obtain a piece of land from Westland which enabled them to build their first track and establish themselves as a club. This site was in use until about 2000 when Westlands sold the land Model Engineer 8 April 2022

ME VISITS A well-made and attractive access bridge over the garden railway. Another section of the garden railway. Bill Edmondson progresses along the very long straight section Being buzzed by a military helicopter! of the club track with his Bagnall saddle tank. Model Engineering club was This is one of the longest 2½ As it gradually expanded, quite a complicated garden thus formed and this is where inch gauge tracks in the UK in the club found that many railway in O gauge. I found I met the present members on regular use and the club holds of the newer members did a very attractive layout my visit. sponsored days to enable not have the fundamental containing some interesting running for other clubs. As skills needed for productive features together with some With about 55 members in this is the only 2½ inch gauge model engineering so one excellent rolling stock and the club they have a fine 2½, track in this part of the country, member offered to run a locomotives. Using SM32 3½ and 5 inch gauge track these days are very popular! basic engineering class for track the layout has been in about 1200 feet in length. those who fell into this group existence and used for about – a group that covered a three years and comprises two The Baguley valve gear on the Bagnall tank. wide range of ages. As this loops on a more or less flat >> progressed it was decided to gradient. Additional steaming start building a simple tram bays were added last year and engine for use on the 2½ inch with the maturing rock garden gauge track with the purpose it is beginning to look a most of demonstrating how things attractive feature. can be done. After expecting about four such engines to be A walk round the perimeter made, this proved very popular of the track gave me a flavour and the total so far is about 14 of some interesting views and so it was a successful venture! driving conditions. The track The club embarked on a boiler itself is made from edge-on building group for these little steel bar supported on wooden engines and this was again sleepers which are fixed to a very successful. Progress has substantial concrete brick wall continued with the building of ensuring a secure base and a good riding track. It has one www.model-engineer.co.uk 517

Bill Edmondson’s 5 inch gauge W. G. Bagnall saddle tank. A fine 5 inch gauge LSWR milk van owned and built by Mike Watson, the club secretary. Simon Wager is building this model of a GWR Saint class A little 3½ inch gauge Tich and coal wagon. 4-6-0 to the Don Young design. of the longest straights I have modified to suit their needs. A useful 5 inch gauge 0-4-0 shunter. seen on a raised track and it They don’t have any power runs parallel to the flying field of Westland Helicopters. This on their site so all the power also leads to some unusual they do have is from solar situations; for example, whilst panels, which suits them I was being driven round very well, and for any mains the track by Bill Edmondson power they need they have a with his 5 inch gauge generator. The winter evening Bagnall saddle tank 0-4-0, we meetings are held in a nearby were ‘buzzed’ by a full size church hall. helicopter during a test flight! Members enjoy their track Bill’s engine is a compact, days and of a membership well-built example of a Bagnall of 55 there are 35 members tank locomotive and is fitted or so who regularly attend with Baguley valve gear. It which I think is a tremendous performed well around the response and a credit to the track with plenty of power for club. Some of the remaining two passengers. members still contribute when they can and using the modern There is a quite well concept of the ‘Men’s Shed’ equipped club room which idea the club maintain a happy came from the merger with and well organised operation. the College club and is still They do encourage different being used, along with some types of model making and substantial storage sheds to illustrate this Brian Gulley provided by steel containers had his 1:10 scale model of a 518 Model Engineer 8 April 2022

ME VISITS A well-made 2½ inch gauge 0-4-2 tender locomotive. A standard Sweet Pea with tender and driving truck built and owned by Bob Richards. This Class 37 was running well around the circuit. This good-looking German Tiger tank was made from Meccano by Brian Gulley You have all heard of Dash Cam - well here we had waggon Cam! German Tiger tank on display, steel rail. As this site is not West Main Line Steam Trust club members, Len White, Bill which he had made from accessible to the public, station in Yeovil which they Edmonson and all the others I Meccano with suitable drive they do not, of course, have operate to coincide with main spoke to for their information units for the individual track public running days but there line steam specials (which and hospitality; it was a and turret - and the gun can are some occasional days, are fairly regular) so this does most enjoyable visit. I went organised in conjunction bring in some revenue. It is away with the impression also fire foam projectiles! with the Westland Leisure only a simple up and down of a happy club enjoying In 2012 the club embarked Centre and some charities, track but it attracts a great their hobby despite all the on a complete upgrade of the when the public are allowed deal of attention when the problems they have endured track replacing the old wooden in. The revenue earned is main line locomotives are along the way - and long may sleepers with new wood shared between them. They being serviced. they continue to do so! polymer composite ones and do, however, have a short, the rails were also changed to permanent track at the South In closing my notes I would ME a deeper 10 x 20mm section like, as usual, to thank the www.model-engineer.co.uk 519

Hotspur constructs a three- cylinder reversible oscillating engine. Continued from p.469 M.E. 4687, 25 March 2022 The writer’s first experimental engine was a single acting four-cylinder unit with a common steam chest housing the two slide valves but there were no extra facilities and no reversing mechanism. A Miniature Oscillating Steam Engine PART4 Last time I described how where shown as this allows disturbing the other. The to add the rear support a coupling to be driven from removal of material by drilling bearing and a similar the lower shaft. Two small the access hole means the process is required for the rectangles of 16 SWG brass heat required is minimised and second extra bearing housing sheet were made to add to the photo 27 shows the way I held in front of plate ‘A’ - this too lower end to form brackets to the block to minimise the heat is bolted to the main frame keep it rigid. to solder the upper plate only. angles. My drawing fig 4 This was then repeated for the shows the details of the The first task is to soft other plate. main brass block which was solder them to the lower squared off at the base and the edges and by using a fine gas The front lower corners of large drilled hole was added flame each can be soldered the two plates must now be on centrally in turn without filed out to fit over the front 27 28 Hotspur may be contacted The two side plates soft soldered to the front block - the heat The front block with the relief angles filed out on 01600-713913 or soak was sufficient to do both without mishap. to fit over the front frame cross-beam. [email protected] 520 Model Engineer 8 April 2022

O S C I L LATO R Fig 4 Front bearing pedestal. 1” 1/4” Ream Ø5/16” for r5/16” bronze bearing Finish profile 13/16” Ø5/8” 2 off 7BA bolts into 1 5/8” 1/8” (bare) main angle 9/16” 1/2” Soft solder 1/16” 3/4” 5/8” 1/4” sq. - file 7BA clear for bolts away to fit over through lower angle lower frame angle Initial Brass Fabrication For Front Bearing Pedestal M/C Ops. For Bearing Pedestal 29 30 A trial assembly shows the front bearing block on the main angle frame and squared up ready to drill and spot through the holes for the fixing bolts. cross-beam angle to which this shows the task completed. Do square to the base so the bolts for the ⁄516 inch hole to be drilled will not pull the bearing away and reamed. Photograph 31 new block will also be bolted make sure that the bolting face from the vertical. shows the task being set up with the two centres method for stiffness. Photograph 28 on the main frame angle is The block assembly can but, in addition, the dial gauge was turned around in line 31 be fitted to the main frame with the lathe axis to check and squared up as before and the outer face of the block The front bearing block set up in a small four-jaw chuck to centre the journal hole. held with clamps as shown in was square before the hole >> photos 29 and 30. Initially the was made. Also shown is an two 7BA clearance holes for extra packing block added the bolts that secure the block on one side of the chuck to to the front angle were drilled assist with the balance of the through and used to spot the work and the scribed outline holes in the lower angle. Make of the eventual shape of the sure the centres for these block is also evident. The addition of the bronze bearing holes are less than ⅛ inch followed the process for the from the bottom edge so the rear arrangement and is shown addition of the fastenings to in photo 32. The driven shaft the angle is not restricted. will also be left long enough After all the six fixing bolts for a flywheel to be added, if have been fitted, the pointed considered necessary. shaft can be used again to mark the bearing block and the assembly centred in the lathe www.model-engineer.co.uk 521

32 33 The wider section of the crank parts held to counter-bore the end with a slot drill to sit over the crankshaft bearing bush. The complete front bearing arrangement and the test shaft rotates quite easily despite there being six journals! Making the The composite crankshaft reamed ⁄3 16 inch hole through the ‘A’ plate so they can be crankshaft parts consists of three pairs of the centre and then a ⁄3 32 inch kept matched together. All of cranks and discs that are reamed hole, ⁄9 32 inch off-set, them will need to be cut into With both additional bearings initially in one piece and through the total thickness to in place, work can commence machined from round bar to be the crank pin location. It is two pieces and finished at ⁄5 32 on the crankshaft parts and best if each pair is given two inch thick and ⅜ inch thick my drawing fig 5 shows a be faced flat on both ends numbers on each end of either, respectively and the thicker general arrangement of the and ¾ inch long overall. This 1, 2 and 3 or A, B, and C from half can be machined to size items needed and their details. stub of material requires a in the three-jaw chuck easily enough. Fig 5 0.27” Crank details. 2 1/4” I actually started at Plate 25/32” 2 3/8” ‘A’ and photo 33 shows the first wide section of crank D 5/16” A material held in the lathe to be Socket grub screw C (x3) B faced to width and counter- bored 0.4 inch diameter by Crankshaft Assembly G.A. ⅛ inch deep. Before splitting 9/32” Ø3/32” 5/32” thick 3/8” finished thickness this section into two parts, Ø1” finished after the next task is to drill the s/s shaft to Ø0.4” Notes: crankpin hole and great care cut face Crank pin to be a tight fit was taken to ensure the in main crank disc material was held squarely Crank throw Ream Ø3/16” 1/8” C/bore with Add crank pin clearance in and then positioned over the slot drill soldered disc slot in the drilling table so Add 1/32” flat for grub screws the drill could break through to suit 120° timing on the underside. My next Check crank pin silver steel picture photo 34 shows how dia. prior to hole drilling the short length of material was held on its side in a vice Drill shaft & crank pin to perform this operation. holes before separating This task could have been done in a four-jaw chuck but checking the accuracy of the drilling afterwards proved satisfactory. The stub of bar was then sawn carefully to provide the two parts that will sit either side of the first piston rod. The wider section was easily held in the three-jaw chuck again 522 Model Engineer 8 April 2022

O S C I L LATO R 34 35The length of crank material for a pair of drive parts is held in a vice to drill the crank pin hole right through and the counter-bore hole added to give clearance over the plate bearing. Here the narrow section of the crank assembly is being set up to silver solder it to a short length of shaft. After acleaning up the part is faced to thickness. to clean up the cut face to The wide disc requires a Each crankpin needs to be parts were dismantled it was thickness. The narrow section radial hole to be drilled and at 120 degrees to the next one seen that the flat on the shaft of the bar now needs to be tapped for an Allen grub and I found that a simple pencil for the grub screw was too near silver soldered to a 2½ inch screw that will secure it to the mark on the discs at 20 past the end of this shaft. Making length of ⁄3 16 inch shaft to drive shaft for the section next to it the hour and 20 to the next the flat longer allowed the shaft though the plate ‘B’ bearing between plates ‘B’ and ‘C’ and hour sufficed for the settings. to go fully into the crank and and through into the next wider either 4BA or 2BA can be used Photograph 36 shows the restored the clearance. section of shaft. I trust it is for these fastenings. Repeat results and should clarify the clear that each section of the this process with assembly 2 descriptions. Keen eyed readers So, at this point I turned the crank assembly will have two and here the shaft is a similar will see that I added a rebate on engine over by spinning it in parts of the brass rod cranks length but for the third pair of the crank to fit against the ‘A’ the lathe. The collet handle drilled and cut to ensure the crank parts the end shat needs plate, which was not required, fitted onto one end of the crankpin has continuity across to be 2¼ inchevs long but no so I have assembled the crank crankshaft has a centre on end the gap that includes the more soldering is required. section the other way round. of the handle so it was easily piston rod. Do make sure that Where the two short stubs of mounted between the chuck each piece is marked to ensure shaft and the one longer shaft With all the parts assembled and a tailstock centre and, correct assembly. are attached to the cranks, it should be possible to turn resting on the top slide, it was each has to be given a flat for the engine quite easily but I well oiled and slowly rotated. For the two pairs of parts the seating of the Allen grub noted a tight spot during one Running for 10 minutes at behind plate ‘C’ and plate ‘B’, screw but this should ideally rotation. It was traced to one of around 100rpm, it was found to the narrow discs require a ⅞ be done once all the parts are the pistons rubbing against the be very free to turn by hand and inch length of drive shaft to available. For convenience adjacent disc when the piston so attention could turn to the allow some of the length to each tapping can be at 180 was at the bottom of its stroke; next stage. ●To be continued. protrude above the disc section degrees to the crank pins. The there should of course be a for silver soldering so check larger assembly again has a witness of light down each side NEXT TIME the length on the assembly. To short shaft silver soldered to of all three pistons to signify ensure the solder will penetrate the narrow disc but the wider that sufficient clearance exists. We deal with the worm drive well down into the joint use a crank section that also needs I also noted that the short shaft assembly and the water 60 degree countersink and add a tapping for the Allen grub from the disc into the adjacent pump drive. a useful chamfer on the central screw. crank part had not gone fully hole in the sawn face first. The into the hole and when the fabrication was then cleaned up and held in the chuck to 36 machine the sawn end face down to the ⁄5 32 inch thickness. Here all the crank parts are set-up to show how the assembly is arranged and the wider Photograph 35 shows the components have had their tapped holes added for the securing grub screws. parts ready for the soldering task. Each main crank section was fitted with a short length of ⁄3 32 inch diameter silver steel using ‘Loctite’, to be the crank pins. Each pin needs to be a running fit in the adjacent disc to avoid any chance of binding so be careful with the drill sizes used. www.model-engineer.co.uk 523

Give Your Articles a PART 1 Boost with QR Codes! Luís Trincão Introduction At the beginning of this helps century, we witnessed the very to bring Written communication rapid expansion of a support written communications (education, science, marketing for transmitting even faster into the 21st Century. etc) is often complemented and more reliable information with information on the Internet or with shortcuts in – the optical fibre. QR1 - The quick brown fox… the operation of our computers The ease and speed with and smartphones. smartphones. QR Codes play which we currently access the an important role accelerating In the early days of the Internet would be considered access to websites on the Internet, access was made almost a miracle in the 1990s Internet, but also in sending by connecting a device called but it has made us more emails, text, SMS, transferring modem between the computer money or even making phone and the telephone line. No Wi- intolerant of delays or difficulty calls. Fi like now. The telephone line in accessing information. If consisted of a pair of copper refreshing a website screen Compared to bar codes, they electrical wires that could is slow or if we are required contain much more information not be used for conversation to type a very long website and are more reliable. There while accessing the Internet. address in to a browser, many is also redundant information, The data transmission speed of us will give up. which in certain cases allows was very low and unreliable. us to read partially damaged A screen could take several The aim of this article is code tags. minutes to refresh. to teach you how to take advantage of QR Codes in QR Codes were invented by Then another technology various situations; explaining the company Denso Wave, a called ISDN (Integrated what they are, how to read subsidiary of Toyota, and have Services Digital Network) and how to create them. I ask their origins in the tracking of came, allowing higher speeds forgiveness from the most parts and vehicles during the and reliability as well as experienced for the basic manufacturing process. Denso simultaneous voice and data nature of parts of this article. Wave owns the QR Code patent communication. but stated, however, that they This article was written would not exercise their rights, At the same time, mobile based on my Android 11 thus making this invention telephony was evolving from a smartphone. The options I accessible to everyone. voice only technology towards mention may differ for other voice and data integration. versions of software. Using Fig 1 IOS smartphones (iPhone), presents slight differences but the procedures are very similar in general. Whenever in this article I refer to a smartphone, it is also valid for a tablet. Finding the camera. What is a QR Code? Let's start reading QR Codes The Quick Response Code or QR Code (see QR 1 for an We start trying the simplest example) may be considered way, which is to use your an evolution of our well- smartphone's camera (fig 1). known bar code present on Your screen will be different, all the products we buy in but the important thing is to supermarkets. It consists of a square grid of pixels that find the camera icon. Open the can be read by specialised Camera application and point optical readers or by ordinary it at the image at the beginning of this article - QR 1. 524 Model Engineer 8 April 2022

QR CODES If all goes well, a text will be Fig 2 Fig 3 displayed on your smartphone that starts with: “The quick Confirm you want to read the code. Here is the text. brown fox…”. Depending on your smartphone’s Fig 4 Fig 5 software, confirmation may be requested to view the complete text (fig 2). Click on that area and you have the result (fig 3). You can change and save the text on your device if you wish. Note that at this stage it is not necessary to have Wi-Fi or mobile data turned on because this is a text only QR Code. If your camera doesn't detect the QR Code, it could just be a configuration issue. Check as follows: • Fig 4 – Tap Settings. Go to the applications. • Fig 5 – Tap Apps. • Fig 6 – Find and tap Camera. Finding the settings. • Fig 7 – Tap Camera settings. • Fig 8 – Activate the Scan QR Codes option. • Exit Settings and try again to read the QR Code. If, in the above check, you Fig 6 Fig 7 cannot see the option shown Select the camera. Check the settings. on fig 8, your camera probably just try another one. Install does not support reading QR your chosen App. QR Codes, I suggest reading websites, it is necessary to Codes. You must then install three QR-Codes that will take enable Wi-Fi or Mobile data on an App (Application) that does Assuming that your you to websites on the Internet. the smartphone. See fig 10, the reading: smartphone is now able to read As we are now accessing taken from the smartphone's Open the Play Store App (fig 9). Then, choose a program to install. Check the average review rating, the number of reviews and how many downloads were made. I did a search for QR Code readers and advise you to install programs with a rating average of at least 4.5 and at least 5 million downloads. Anyway, if you don't like the installed App, Fig 8 Fig 9 Fig 10 Turn on QR Codes if present. You can buy a QR Code app here. Making sure you have access www.model-engineer.co.uk to the Internet. >> 525

Quick Panel. Activated options QR 2 - Modem sound. QR3 - Model engine. !$ 4 - Portuguese National are shown in blue. Railway Museum. Reading QR 4, you can Point the camera at QR 2. access the Portuguese Is it safe to read such as the QR Scanner from You will have quick access National Railway Museum QR Codes? Kaspersky that can give us to a video on YouTube with Website. greater sense of security, sounds emitted by an old A QR Code presents the same especially if associated with data transmission modem. Pay attention that a QR risks as using an Internet an antivirus. For the younger generations Code linked to content on browser. If we access a it may be a novelty, but for the Internet only works while website via QR Code and it In the second part of the the less young like me, it's the address encoded exists. asks us for critical information, article, you will see how QR nostalgic and reminds me If a particular page on the we must be as careful as Codes can be generated. of long waiting times for my Internet changes address, it with any access done using computer’s screen to refresh, is necessary to create and a browser. There are QR Code lTo be continued. praying that the phone call publish new QR Codes. reader programs made by anti- wouldn't be interrupted. virus protection companies, The QR 3 example links to a video that complements the article I wrote; CAD and 3D Printing in Model Engineering in this magazine (issue 4676). At the time it didn't occur to me that I could use a QR Code to promote the video. Depending on your smartphone settings, you may be asked to confirm your Internet connection. NEXT ISSUE Flying Scotsman Content may be subject to change. Peter Seymour-Howell manufactures the centre cylinder for his 5 inch gauge super detailed Flying Scotsman locomotive. Federation AGM John Arrowsmith reports from the Federation of Model Engineering Societies annual general meeting held at the Avoncroft Museum of Historic Buildings at Bromsgrove. Ballaarat Luker pipes up the smokebox for his 5 inch gauge Australian locomotive and adds a mechanical lubricator. Astronomical Clock Adrian Garner concludes his description with some words about polishing. Brushless Motors Brian Gawthorpe continues his description of brushless DC motors by discussing his sensorless motor drive. Little Demon Mick Knights turns the block over and mills out the crankshaft pockets for his V8 internal combustion engine. ON SALE 22 APRIL 2022 526 Model Engineer 8 April 2022

The Little Demon Supercharged V8PART2 Mick Knights describes the construction of a supercharged V8 internal combustion engine. Continued from p.430 M.E. 4687, 25 March 2022 Starting the build very little room for error and There are two deep drilled >> the position of any one part 0.062 inch diameter holes The only help offered in the directly impacts on others. on both banks close to the plans is for the initial machining back face of the cylinder of the cylinder block. I would After rough machining all block. The only instructions suggest that a little time is mating faces are finished by regarding these holes are to taken to familiarise yourself fly cutting in order to ensure tap them (I use M2) as deep with the orientation of the block they are as flat as possible to as possible - no explanation as and the offset position of the eliminate the possibility of fluid to why is given. If I’d sat and right and left-hand cylinder and gas leaks on final assembly thought about it I might have banks. This gets easier as the and eventual running. worked out their purpose but machining progresses but I only fully realised what they there’s a detail on one of the I will also be using were for when I was reading cylinder heads that is slightly aluminium tooling plate for the sheet regarding timing different from the other and the majority of the smaller the engine. What happens that’s regarding the cooling flat components. I shall is two lengths of 0.062 inch water circulation port - the explain why when we come to silver steel are inserted in the corresponding detail of this machining the first ones. holes and tightened down port has to be incorporated on against the outer casing of the the left hand bank of cylinders Cylinder block camshaft rear roller bearing on the block itself. with M2 grub screws. The The first machining operations inner diameter of the ball race The initial machined block are to produce the cylinder is bonded to the camshaft, is oversize to allow for the block to the dimension shown so clamping on the outside machining of the side reliefs on the initial machining diameter of the bearing has at a later stage. I cannot over- drawing, to establish hole the effect of holding the emphasise that the machining centres, drill two cooling camshaft in position. More must be as accurate as water circulation holes and to on this subject much further your situations allow, as on establish the positions of, and an engine this size there is produce, eight cylinder liner bores. www.model-engineer.co.uk 527

12 Squaring up the block. Accurate placing of the first holes in the block. 3 4 Drilling the first four bores in the block. The bores are finished with a slot drill. on, but for the moment these without saying that these sometimes produces slightly finish (photo 4). There is an holes should be included at centre positions need to be different results, especially accurate depth dimension to this stage. established as accurately due to tool tip wear and push the bottom of these bores; as possible on each end off (photo 3). The bores are this needs to be observed as it The end faces must be face. To avoid disorientation finished using two slot drills, creates a lip where the cylinder when drilling from either end the second removing as little liner will locate and acts as a machined to finish length and I roughly mark the positions material as possible in order positive distance stop. This be as square as possible to with a felt tip pen before to maintain size and surface location lip will manifest itself all other faces as these faces should not really be revisited. removing any metal. The first 5 To achieve squareness the holes are established and block was clamped against an The block now has all eight bores. drilled using a standard ⅛ inch angle plate and fly cut. I tend jobber drill as deep as the drill to use a boring head for this operation as it supplies rigidity flutes will allow before joining and can be easily adjusted to front and rear holes using the long series drill (photo 2). fly cut small or larger surface areas (photo 1). The right and left banks are The cooling water circulation marked for easy identification bores have to be produced at these early stages of before the cylinder bores as machining. The bores are these holes pass through the initially centred, rough drilled liner bores themselves. These to depth and finished to size holes, being ⅛ inch diameter, with a sharp slot drill. Using need to be established a slot drill will ensure that all and drilled from both end bores are an identical diameter faces, then joined by using - boring eight diameters at a long series drill. It goes one setting with a boring head 528 Model Engineer 8 April 2022

LITTLE DEMON 67 Milling out the valleys. Finishing the profile of the valleys. 8 9 Adding all the other holes to the block. Machining the top faces and the top of the ridge in the valley. after the three pockets that they cannot escape into the material has to be removed to cam follower guide bush bores allow crankshaft rotation are lower crankcase, while at the and oil return holes. machined in the bottom face top end they are fully retained finished depth using a larger of the cylinder block at a later by the cylinder heads when diameter cutter and the corner To finish the top end, the stage. Photograph 5 shows fully tightened down. I decided detail produced at a second billet is set at 45 degrees to the cylinder block with both to turn the entire length of the visit. The bulk of material is machine the top faces and cylinder liners to the same also removed from the second the internal ridge in the valley banks bored to finished size diameter as the top counter valley area - these pockets are (photo 9). These days I use a to accept the steel cylinder bore shown on the drawings. handed and so care needs to magnetic digital angle setting liners. This allowed me to turn be taken (photo 6). block, as they are accurate to the radial water circulation a tenth of a degree, which is Some future photographs area as a recess into the The finished profile of the plenty good enough for this of the cylinder block will show outside diameter of the liner valleys is now produced on type of machining and is a the cylinder liners bonded itself, which has exactly the both pockets (photo 7). whole lot easier to use than in position. Anyone familiar same effect as producing juggling a protractor or, in a with this particular engine, or eight radial pockets in the From now on every hole fully equipped workshop, a are in receipt of their own set cylinder bores and avoids position has a direct bearing stack of slips and a sine bar. of plans, might have noticed a complicated machining on all the others and any errors that the eight radial water operation and the purchase of that are allowed to accumulate ●To be continued. circulation pockets that are an appropriate Tee slot cutter. would have consequences. machined into the walls of Wherever possible all the NEXT TIME the cylinder bores have not The next series of operations establishing of centre been produced by this stage. produces the valley area. positions and drilling holes on We turn to the bottom face There’s a simple explanation each bank should be carried of the block and the sump. for this. As the cylinder liners The final valley area has out at one setting to ensure are bonded into position and 3mm radius corners that are concentricity. Photograph 8 are retained by the lip at the produced with a 6mm diameter shows all the cylinder head bottom of the cylinder bore cutter, so the bulk of the securing holes, cylinder head cooling water transfer ports, www.model-engineer.co.uk 529

The Aftermath! 1 Geoff Behind that cryptic remark lies Leeds hospitality! (Photo courtesy of Pete Nash) Theasby a story, which doesn’t apply reports happened. His trolley pole had never electrified and finally on the latest news in this case, but suffice to dewired and brought down all abandoned in 2005 amid from the Clubs. say, your scribe has been the overhead for about half proposals to turn the building beavering away at this a mile… - Geoff) Pete Nash 530 column such that you, was also well travelled - he into flats, whereupon the Dear Readers, see only survived a trip to Leeds despite council listed it. Despite being a seamless segue from the train annunciator stating, promised the sheds would the previous issue. So “We are now arriving in Leeds, be preserved, the building much so, in fact, that where this train terminates ‘fell down’ one night. The Deborah took me away for passengers…”. With a photo the weekend in Nantwich. to boot (photo 1). 'What’s an edifice, with its large carved (Centre of the known annunciator? A senior Roman stone ‘Sheffield Tramway Catholic priest?' Company’ sign, was eventually universe...) (So you followed W. www.cdmes.co.uk rebuilt, and altered to allow her back, then… Ed.) emergency vehicles in, but Steam Whistle, January, from it had lost its authenticity. In this issue: Pink Floyd, In the February edition, all ‘another brick in the car’, Sheffield Society of Model becomes clear about ding dewiring, dings, a rotating & Experimental Engineers separators. Murray suspects statue, a ‘Technicolour’ truck, has lots of pictures of work it is a separator made by and bayonets. being carried out at the track, Myron Dings of Wisconsin. which proceeded by leaps Well, of course it was! How The last Stephenson Link of and bounds in the absence could we not know this? 2020-21, from Chesterfield of passengers getting in the Separators, as any fule no, use Model Engineering Society way. Mike Peart, in ‘What’s belts and magnets to divide has a new editor, John Walker, my line?’, discussed the up an amorphous mixture who is settling in nicely, and odd occupations that the into its constituent parts, thanks his contributors for programme’s guests had. ferrous/non-ferrous metal for their labours. These club In the introduction to the instance. There, now what magazines often carry adverts railways, he listed the various good’s that done yer?! for members’ workshop specialities, not just the W. www.sheffieldmodel equipment but a new one celebrated wheeltappers, but here is a 1935 Austin 7 also shinglers, scraggers, engineers.com Ruby. With an 800cc engine, boshers and so on. One The Frimley Flyer, January, compression ratio of 4.8:1 such eluded Mike - a ‘ding from Frimley & Ascot and a non-existent 0-60 mph separator’. What dings Locomotive Club, shows the time, it returns 45-50 mpg. were and why they needed superb condition of their track, £5,500. Peter Hawkins writes separating appeared to be one all ready for the onslaught. on machine tool-maker James of life’s mysteries. Editor Mick Nick Moore has been wielding Fox of Derby. One of his lathes Savage relates the strange the leaf blower; editor Andrew is at Wortley Top Forge near Dougless fears that it may turn Barnsley. It is dated to 1821 tale of Sheffield’s Heeley into a man-lifting drone if he by reference to Graces Guide tramsheds. Used solely gets too enthusiastic. He has and is 11 inches centre height for horse trams, they were serviced it recently, to great x 5ft 6in between centres. It is accurate to 5 ‘thou’, good for the time and its age. Fox’s early life was as a footman to a minister. He spent his spare time using tools available to him, his employer noticed and encouraged him in starting a manufacturing business. Jack Brown writes on his Aveling & Porter roller, Prince Albert, of 1901 The January issue relates that editor John travelled to Prague and discovered the results of a tram pantograph getting entangled with the overhead. (I recall that my first wife’s father drove trams in Bradford and one day he was coasting down a long hill with the power off, then when he got to the foot of the hill and operated the controller, nothing Model Engineer 8 April 2022