Inhoudsopgave van Issue 4708 - Model Engineer

125 Not Out! The very first issue of our magazine was published in January 1898 so we now have the rare distinction of having been published continuously for 125 years. In fact, we may have the distinction of being able to claim an even greater anniversary than that. Reader Bob McFiggans wrote to me recently explaining why: ‘Year 2023 may turn out to be somewhat more important than expected. Let’s see what your predecessor Martin Evans (Mark I) had to say for our 75th year (M.E.3456, January 5th 1973): As we enter our 76th year of publication, perhaps I may be excused if I may, with our editorial staff, indulge in a modest amount of selfcongratulation. Very few magazines have been published continuously for 75 years. Added to this is…

My locomotives are mostly restored/renovated bits and pieces of unfinished projects and do not have a working boiler because they are solely intended for display and certainly not for steam. My pleasure comes from restoring and completing a representative locomotive to a good standard. It’s this that keeps me busy in the workshop and manages to keep the little grey cells occupied. In the past I have failed miserably to silver solder a working boiler so my locomotives are fitted with a dummy boiler or casing. Creating a record of the work completed, and writing up the projects, is an added bonus which I enjoy and, in most cases, Martin Evans, our editor, has been happy enough to share them with the readers of Model Engineer. Tackling projects with left-overs…

GRASSHOPPER Item 21 - Link Anchor Mount (figs 32 and 33) 10mm 5038 Aluminium plate This mounting plate serves two purposes - firstly to provide a bearing for the shaft transferring the movement of the cam follower to the valve spool, and secondly to provide an anchor point that controls the position of the beam using links to create a parallel motion, enabling it to be connected to the piston rod. To carry out that function as a minimum it requires a slot, six drilled and one reamed hole provided in a rectangular plate having a slight reduction to its width at one end. Should the constructor want to keep machining to a minimum that is all they need to do, but the result will look very ‘BLOCKISH’, which may…

The second incarnation I thought carefully about how best to support the motor and yet measure its torque. It occurred to me that by mounting the motor on a pivoting cradle, the motor could be located in a fixed position but the cradle could be supported on pivots which were directly co-axial with the motor shaft. In that way, the motor would be free to rotate yet be rigidly fixed in all other axes. The torque could then be measured quite simply by restraining the motor using a fixed arm pressing down on a set of scales. I considered that if the motor were to drive the dynamo by a belt, then the dynamo speed could be increased from the 720 rpm on the low speed to a speed more…

TRAM For a while I’d been hankering after a new project. Something small, different and fun. I flicked through a few engine books and magazines looking for inspiration until I spotted the very thing; a 7¼ inch gauge steam tram based on the Y6 engines that chugged up and down the Wisbech & Upwell tramway in the fens, as well as in a few docks in East Anglia. This type of locomotive was made famous by the Rev. Wilbert Awdry as ‘Toby the Tram’ in his Thomas the Tank Engine series of books. The particular locomotive that I’d stumbled upon in the magazine was something a little different, in that it was powered by a 3½ inch gauge ‘Betty’ chassis and ‘Maisie’ boiler! A chain around the ‘Betty’ driving axle…

HIT AND MISS Piston and connecting rod Moving on to the piston and connecting rod. Rather than carve something out of the solid, I decided to cast one from gunmetal. While I was about it, I also cast the main bearing shells (photo 18, fresh from the sand, with 3D printed patterns). The rod was drilled, cut, bolted back together and bored (photos 19 and 20). The main bearing shells were faced, soft soldered together, machined (photo 21) and un-soidered. To stop them rotating in the housings, a small hole was drilled right through and into the base, then a suitable pin was inserted. Now for the piston. A solid bar was supplied, the idea being that the piston would be carved from this. I went for a casting. Photograph…

Brought up reading Model Engineer in the 1950’s and early 60’s I innocently believed that the one thing model engineers never, ever, made were mistakes. True, there were occasional references to ‘Railroad Esperanto’ when something went wrong but few writers ever admitted to errors or failures. Reality is different. Talk to top model engineers and you'll find that even they have made mistakes. As that experienced model engineer exhibition judge Ivan Law says “the man who never made a mistake never made anything” (photo 1). Even Cherry Hill made mistakes making her exquisite models but in Cherry’s case errors came from following 19th century mechanical engineering journal drawings that weren’t always accurate, notably those for her Law and Downie road locomotive (ref 1). Not Cherry’s fault and decidedly high-class mistakes…

It was clear that the overall appearance of the locomotive was going to be influenced by the quality of both the paint finish and the fit of the boiler cladding. It may have been possible to just wrap a sheet of light gauge sheet metal around the boiler tube and secure it somehow with the external banding. The right way, though, to do it is to support the cladding, or ‘clothing’ as it is sometimes called, on a framework of steel bands called crinolines. These also provide mounting points for the handrail stanchions that would be screwed directly to the boiler on the full-sized article. Before that a short digression; a fascinating look at the detailed specification that was drawn up by the railway company for the guidance of bidders…

Adding the top fittings to the boiler Back at the start of the boiler construction, I included a picture of the materials I had purchased and it showed the top casting that had already been machined to fit the top of the boiler and to receive the length of brass tube for the chimney. When I introduced the boiler construction it was not clear to me where the materials had come from but I can advise that the top casting has a number 109 on the underside. The task now is to locate the pre-turned casting on top of the boiler and arrange for the steam outlet valve and safety valve fittings to emerge through the cast bosses that have been included on it. It has had to be assumed…

FLYING SCOTSMAN Cylinder relief valves Continuing with the various parts to fit to the cylinders, this time we have the six relief valves. To be clear, these are the other relief valves, in addition to those incorporated into the drain cocks. I have followed Don’s overall dimensions but added extra detail and made them fully working and easily adjustable to what I feel is perhaps close to how the full-size work. I have no works drawings for these so the innards are to my own design. The body of the valve begins life as some 7⁄16 inch bronze hex. I started by turning down the middle section, drilling the centre, deep enough so that when parted the hole was right through and then machined the chamber using a 3⁄16 inch…

CLOCK Balls cage and lifting arm The cage holding the balls has 12 slots with six populated on one side by ⅝ inch stainless steel ball bearings. The two plates of the cage, 1.2mm thick, were initially bolted together and 12 equally spaced 25.4mm holes machined at a radius of 62mm. The shape of the cage was then cut with a scroll saw using a computer generated pattern glued to the plates. On the clock the two halves are kept apart by 11.4mm spacers and rotate around a fixed cylinder on a pair of ball races, O.D. 12.7mm ½ inch) and I.D. 7.938mm (5/16 inch). The lifting arm fits behind the balls cage, rotating on similar ball races about the same cylinder (photo 9). A 48.6mm O.D. contrate wheel with…

This contest brought back memories of my own classic clanger though as editor of the York Model Engineer’s Newsletter I felt it inappropriate to enter the contest. My father taught me how to cut screw threads on the Lathe. So when I wanted to make an arbor for some slitting saws (1 inch internal diameter) he offered advice and presented me with a nut from the family archive of nuts and bolts. (Every home should have one.) It was a magnificent specimen - 1 inch internal diameter, 8 tpi Whitworth thread (photo 4), I made the arbor (perhaps better described as a spindle) as a Length of 1.25 inch diameter steel,one end to be held in the chuck and the other held against a centre. This arbor was reduced in…

January 15 North Wilts MES Public running at the Coate Water Railway, 11:00-17:00. See www.nwmes.info 17 Taunton Model Engineers Meeting, Stoke St. Mary village hall, 19:30-21:30. See www.tauntonme.org.uk 18 Bristol SMEE Small, non-locomotive engines evening, Begbrook Social Club 19:30. BS16 1HY. Contact: secretary@bristolmodelengineers.co.uk 19 Warrington and District MES Talk - Dr Mark Caplan, ‘Enter with caution - X rays’, St Mary Magdalene Church, Appleton Thorn, 20:00. See www.wdmes.org.uk/events 22 North Wilts MES Public running at the Coate Water Railway, 11:00-17:00. See www.nwmes.info 29 North Wilts MES Public running at the Coate Water Railway, 11:00-17:00. See www.nwmes.info February 1 Bradford MES Talk - Geoff and Mary Twentyman, ‘The Low Moor WW1 Explosion’, Saltaire Methodist Church, 19:45. Contact: Russ Coppin, 07815 048999 2 Sutton MEC Bits and Pieces evening 20:00. Contact: Paul…

In Part 4 of this series, following an eventful visit to an exhibition in Brighton, the now thirteen-year-old author had started building Rob Roy, a 3½ inch gauge 0-6-0 tank locomotive designed by Martin Evans (no, the other one). Rejoining the tale, the time had arrived where he had something cylindrical to make and, unfortunately, nothing upon which to make it. A new friend In 1981, probably unlike today, it was common for secondary modern comprehensive schools, as they were then known, to force hordes of their male inmates upon the incumbent masters of the artisanal crafts. These shy and gentle souls, in turn, tried, and generally failed, to force some of their hard-won knowledge into their charges and make the best of a very, very bad deal. Put simply,…

Geoffrey calling, Geoffrey calling, Geoffrey calling, this is the Firth Park Technische Funk Meister mit der Gesellschaftsnachrichten. I received a great note from Nigel Bennett of Leeds SMEE about my ID’ing the steam wagon seen in a picture in Aizlewood Mills, Sheffield and mentioned in M.E.4704 (photo 1). He says, ‘Yorkshire Steam Wagon … I’ve looked it up in my book on the subject by Maurice Kelly, where he appends a list of those made. It says: No. 1018 reg U 4625 was built as a 3 ton 3-way tipper on 3-5-1918. Its second owner is given as J & J Dyson of Sheffield. Presumably that’s the one. You also mention Dyson becoming part of Dennis Eagle, who later took over … the Yorkshire Patent Steam Wagon Company. I worked…