Sommaire pour Issue 4688 de Model Engineer

Men’s Sheds Before the covid pandemic brought everything to a shuddering halt I used to attend an evening class, held at a local school on Friday evenings. Moves to revive the class have proved fruitless, sadly, with the school no longer prepared to accommodate us. I have no idea why, as no reason was given. That leaves a small group of rather disappointed model engineers. The class was as much about coffee, biscuits and a chat as it was about making progress on our latest projects and is much missed. Many model engineers must find themselves in similar situations. This is one of the many casualties, I suppose, of covid-19. Fortunately, there is an alternative to evening classes. The ‘Men’s Sheds’ organisation (menssheds.org.uk) is a growing movement to establish places…

Rex Hanman reports on last year’s rally and gives notice for this year’s. As with so many other events, the 9th Rob Roy gathering in 2020 was a Covid casualty. All previous meetings had taken place at the Andover club’s track in Hampshire but a different venue had been planned for a change. With eased restrictions and the outdoor nature of the event, the rally finally took place at Bromsgrove in September 2021. Once again, after a day of heavy rain, the weather was favourable. The author had a somewhat late arrival at the Bromsgrove track as a result of solving a heinous murder that took place on the Bluebell Railway the night before (a highly recommended evening if you like ‘Murder Mysteries’). Loyal attendee Chris Orchard was already whizzing…

Ted Hansen replaces Westbury’s original with a more prototypical gearbox. The intermediate gears The intermediate gear set consists of the countershaft (fig 11) and the idler gear (figs 12 and 13). The countershaft is made up of four gears silver soldered to a central sleeve (photos 16 and 17). Apply silver solder only to the outside edges of the gears -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 mounts on a shoulder bolt against the right-hand side of the case. The shoulder…

Luker argues the case for considering the adoption of TIG welded stainless steel boilers. The boiler data pack For critical welds, which in a boiler are all of them, each weld needs to be properly described. This is called a Procedure Qualification Record (PQR) and typically includes parameters like the amperage, gas flow, rod types and sizes etc. Photographs of all of the weld preparations and general fabrication should be taken and added to the data pack with the material certificates and other necessary documentation to be reviewed by the boiler inspector. Our poor boiler inspector gets a DVD with every weld prep., material heat number, boiler design report and calculations etc. but that’s how it should be. Weld samples of each weld should be welded in the form of…

Luís Trincão helps to bring written communications into the 21st Century. Introduction Written communication (education, science, marketing etc) is often complemented with information on the Internet or with shortcuts in the operation of our computers and smartphones. In the early days of the Internet, access was made by connecting a device called modem between the computer and the telephone line. No Wi-Fi like now. The telephone line consisted of a pair of copper electrical wires that could not be used for conversation while accessing the Internet. The data transmission speed was very low and unreliable. A screen could take several minutes to refresh. Then another technology called ISDN (Integrated Services Digital Network) came, allowing higher speeds and reliability as well as simultaneous voice and data communication. At the same time,…

Geoff Theasby reports on the latest news from the Clubs. The Aftermath! Behind that cryptic remark lies a story, which doesn’t apply in this case, but suffice to say, your scribe has been beavering away at this column such that you, Dear Readers, see only a seamless segue from the previous issue. So much so, in fact, that Deborah took me away for the weekend in Nantwich. (Centre of the known universe...) (So you followed her back, then… Ed.) In this issue: Pink Floyd, ‘another brick in the car’, dewiring, dings, a rotating statue, a ‘Technicolour’ truck, and bayonets. The last Stephenson Link of 2020-21, from Chesterfield Model Engineering Society has a new editor, John Walker, who is settling in nicely, and thanks his contributors for their labours. These club…

April 9 York Model Engineers.Evening Talk – 19:00. Contact: Bob Polley: 01653 618324 10 North Wilts MES.Public Running, Coate Water Country Park, Swindon 11:00–17:00. Contact: Ken Parker, 07710 515507 16 Bradford MES.Easter Bunny 2022, Northcliff Railway 12:30-15:00. Contact: Russ Coppin, 07815 048999 17/18 North Wilts MES. Public Running, Coate Water Country Park, Swindon 11:00–17:00. Contact: Ken Parker, 07710 515507 17 York Model Engineers.Easter Steaming and Family Fun Day. Contact: Bob Polley: 01653 618324 23 Southport MEC.Small Gauges Day, Victoria Park 10:00–16:00. Contact: Gwen Baguley, gwenandderrick@yahoo.co.uk 24 North Wilts MES.Public Running, Coate Water Country Park, Swindon 11:00–17:00. Contact: Ken Parker, 07710 515507 May 1/2 North Wilts MES.Public Running, Coate Water Country Park, Swindon 11:00–17:00. Contact: Ken Parker, 07710 515507 4 Bradford MES.May Meeting - Spring Auction, Saltaire Methodist Church 19:30. Contact:…

Rhys Owen looks at ways of achieving accuracy with a variety of measuring instruments. Verifying squareness The fact that a triangle with sides in the ratio of 3:4:5 was a right-angled triangle was well known in the Ancient World. Pythagoras’ theorem was proved by Ancient Greek mathematicians who also showed that a right-angle could be constructed using a ruler and compass. A precision set square may be used to check that a vertical milling machine’s table is truly at right-angles to the machine’s spindle. Vertical milling machines usually have special surfaces milled in the head casting. A precision set square may be placed on the table and against these surfaces to check the right-angle. Another method of doing the above is to feed the quill downwards and place against it…

Peter Seymour-Howell builds a fine, fully detailed model of Gresley’s iconic locomotive to Don Young’s drawings. Ventilator I decided I would make this a removable item. Firstly, it gives me a better view of the manifold and the various working valves associated with it and, secondly, it will allow more light into the cab and thus help me to see more clearly the controls within. I had originally thought about having the right-angled flange that surrounds the hatch as part of the removable section itself but when looking into this deeper I thought that the joint might be visible due to the flange needing to match the curvature of the roof and remain in shape over time. To avoid such an issue, I decided to permanently solder the right-angled flange…

Doug Hewson presents an authentic 5 inch gauge version of Thompson’s most successful locomotive. Now we have got the underframe completed we can carry on adding several other components to it. I think it would be as well if we put the horn blocks on first of all. They come as gunmetal castings so they will need machining in the usual way. 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. The main thing is to machine the axle box so that it is a very good fit in the horns. The…

Tim Coles constructs a driving truck built for two, in true prototypical style. Body and seat box The body of the truck is made from half-inch thick plywood. I got our local chippy to cut up an eight-foot by four-foot sheet to produce the base, sides and ends of the body, plus a set of parts for the seat box. Unfortunately, I settled for ordinary building grade plywood and, despite careful flat storage, the parts warped quite badly. In future, I will use high quality marine plywood, despite the extra cost. I scribed the side and end panels to simulate the planks of the full-size wagon, using a piece of steel rod suitably pointed at one end. The body and seat box were assembled using white PVA glue, with ad…

Adrian Garner makes a bracket clock showing both mean and sidereal time. This is the time to make up the hardened steel end cap which supports the end of the vertical arbor. This is effectively an end stone and avoids the arbor shoulder bearing on the brass and generating unneeded friction. 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. Re-polish to a mirror finish (photo 124). To mount the…

Hotspur constructs a three-cylinder reversible oscillating engine. Hotspur may be contacted on 01600-713913 or hotspurengines@gmail.com Last time I described how to add the rear support bearing and a similar process is required for the second extra bearing housing in front of plate ‘A’ - this too is bolted to the main frame angles. My drawing fig 4 shows the details of the main brass block which was squared off at the base and the large drilled hole was added where shown as this allows a coupling to be driven from the lower shaft. Two small rectangles of 16 SWG brass sheet were made to add to the lower end to form brackets to keep it rigid. The first task is to soft solder them to the lower edges and by…

Mick Knights describes the construction of a supercharged V8 internal combustion engine. Starting the build The only help offered in the plans is for the initial machining of the cylinder block. I would suggest that a little time is taken to familiarise yourself with the orientation of the block and the offset position of the right and left-hand cylinder banks. This gets easier as the machining progresses but there’s a detail on one of the cylinder heads that is slightly different from the other and that’s regarding the cooling water circulation port - the corresponding detail of this port has to be incorporated on the left hand bank of cylinders on the block itself. The initial machined block is oversize to allow for the machining of the side reliefs at…