Model Engineer的Issue 4704目录

LOWMEX Writing this, I have just returned from the Lowestoft Model Engineering and Model Making Exhibition (LOWMEX), which has made a welcome return after a three-year absence thanks to the covid pandemic. As a show, it goes from strength to strength year on year and it is certainly the most diverse model engineering show that I have seen. It is a show on a huge scale and Kevin Rackham and his team at the Halesowen and District Model Engineering Society are to be congratulated on organising such an impressive event. The beneficiary of the show is S.O.L.D (Special Objectives for the Local Disabled – www.soldstudio.co.uk). The scope of the show is extremely broad, from locomotives and traction engines, through stationary engines (lots of them), boats, tanks, aircraft and miniature fairground…

Continued from p.629 M.E. 4703, 4 November 2022 I'm now returning to the motion and I'm going to start with the Gresley/Holcroft conjugated valve gear for creating the valve events for the middle cylinder. This ingenious mechanism combines the motions of the two outside valve rods, which are 120 degrees apart, to derive the motion for the inside valve, which is itself at 120 degrees to both of the outside valves. This is achieved through the use of two levers, one with bearings placed to provide a 1:1 rocking motion and the other providing a 2:1 motion. These two combined generate the correct timing for the inner valve. 2:1 and 1:1 levers The fulcrum pin has to be accurately placed at a set distance from the left hand inside edge…

‘When eating an elephant take one bite at a time.’ (Creighton Abrams 1914-1974.) ‘….. and try not to choke on the tail.’ (Appended by the Author, who's familiar with the risk.) January 23, 2021. I'm on United Flight 15, somewhere over the Atlantic between London Heathrow and Newark Liberty airport in New Jersey. Many years of air travel are compensated by a free upgrade - small compensation, but much appreciated nonetheless. Thanks to the coronavirus, the plane is nearly empty thirty passengers occupy the three hundred or so seats and I'm torn between writing this article and gazing over the cloud-tops, a sight which never fails to draw my eye. I haven't flown in nearly a year, an unheard-of hiatus, and I'd forgotten the beauty of the view passing the…

Continued from p.647 M.E. 4703, 4 November 2022 The lack of working drawings for the model was a bigger problem than I had anticipated. I had experience of designing my own locomotive when I produced the ‘Charlie’ Southern Q1, but the ‘works’ were very much an adaptation of an existing successful model i.e. Don Young's Derby 4F. Details on the prototype that were likely to be too complex or too flimsy when scaled down were either simplified or omitted as long as the overall appearance remained correct. Hence no footsteps on the locomotive or tender, and Joy valve gear in place of Stephenson's inside motion with rocking levers. However, the L class was going to have all of this and more! Everything on the locomotive needed to be reproduced in…

Continued from p.613 M.E. 4703, 4 November 2022 Electrical testing Please note that when testing electrical equipment operating at mains voltages and above, it is essential that the motor is correctly earthed and supplied through a residual current device (RCD). Ensure that the insulation between each winding and the frame exceeds 50MΩ and test at a minimum voltage of 600 volts and preferably 1000V. After completing the assembly of the motor, I checked the insulation resistance at 1000V between each coil and earth (the motor frame) and between each and every winding, with all insulation values being greater than 2000MΩ. If the insulation value is less than 50MΩ then the cause of this must be found and rectified before continuing. In practice, if you are using good quality polyester enamelled…

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Model engineering is indisputably a very fine hobby but it can also become a true test of character. Some projects (for instance a large locomotive or traction engine) can easily take many years to build, especially if there is a ‘day job’ to attend to. Ten years’ work, or even a lifetime's effort, is not unheard of. Anticipation of the work involved, especially for a first major project, can be quite daunting and there is always the question ‘can I ever finish this?’ One good approach, perhaps, is to deal with each part of the project as a separate task and congratulate oneself on making (for instance) a set of wheels. A pause for celebration follows, and then the next task is tackled with renewed enthusiasm. Steve Goodbody begins a…

Continued from p.589 M.E. 4702,21 October 2022 The grate lifting mechanism The next task is to make the raising mechanism or lifting ramps and the skid that is operated once the ash pan with its grate has been inserted under the boiler. This was an interesting exercise and the additional fixing holes at the back and front ends of the grate are for four more 8BA countersunk screws to attach the ramp assembly. The drawing in fig 16 gives the details and photo 90 shows the side plates cut out of 2mm stainless plate. The overall height of these strips should not be more than ¾ inch. To maximise the lift height in my ash pan, the two end strips that provide the bolting flange for the screws are recessed…

Continued from p.641 M.E. 4703, 4 November 2022 In the last part of this article on the construction of a steam plant, the base had been constructed and the three engines, boiler and ancillary components fitted in place. The next job was to start assembling the pipe runs and fittings. I had a good idea from my layout plans regarding the number of elbows, ‘T’ pieces and valves that I would require to complete the plant and ordered them from the material supplier. I would also require some lengths of 5/32 inch copper pipe and quite a number of union nuts and nipples. Although I have a reasonably well-equipped workshop, I knew I would require some specialist tools for cutting and bending the copper pipe, I wouid also require some…

Continued from p.624 M.E. 4703, 4 November 2022 A Grasshopper Beam Engine Item 13 – Valve Operating Cam (fig 21) Ø50 × 1 inch cast iron Firstly, machine a blank on ail surfaces from cast iron bar to Ø48±0.02 × 18. The stages of manufacture for the cam are laid out in six distinct steps shown in fig 22. Step 1 Settheblank on suitable parallels to bring it just above the top of the vice jaws, with the spindle set to the blank's centre, and the X and Y axis zeroed. Clamp the Y axis slide. Movetheblank to X = -10.25. Re-zero the X axis. Centre drill. Drill Ø7.7 and ream Ø8. Movetheblank to X = 18.25. Centre drill. Drill Ø8 to provide a second hole to be used in…

Continued from p.645 M.E. 4703, 4 November 2022 The Clyde now Next to the Waverley's berth, the Glasgow Tower (photo 11) claims to be the world's tallest fully rotating, freestanding structure. There are good views from the top but not until it reopens in summer 2023. Docks nearby have closed and the Anchor Line ceased trading in 1980. The Queen's Dock, opposite, was filled in providing for a conference and exhibition centre, the ‘Armadillo’ events venue and the Crown Plaza Hotel. The former dock pump house is now the Clyde Distillery offering tours and tastings. Casting off we soon passed the modern Riverside Museum displaying Scotland's transport heritage (ref 4). It is almost on the site of the Pointhouse Shipyard where Waverley was launched. Another addition is the tall ship,…

Waking up on 9 September there was only one thought uppermost in my mind; to visit Aizlewood Mill in Sheffield, for their Heritage Open Day. General manager, Catherine Beatty, took us round, explaining the owners’ family history and the various artefacts saved. A Paternoster lift which was saved from scrapping and, incomplete and not restored to working order, is one of only two extant in Sheffield. A Base Toys, model DA 57, Leyland Octopus model of 1947 - an eight wheel, rigid, flatbed truck in the company livery has been obtained; it may be a promotional model. Its reg. no., HDG153 is not preserved. A photograph from the archives showing a steam wagon outside the Nursery Street mill, has been dated to the 1920s. It is a ‘Yorkshire Patent’ steam…

For the first time in 3 years the Midland Model Engineering Exhibition opened its doors for the 2022 event. The organisers were rightly concerned because after such a long time since the last exhibition they did not know what the response would be like from the trade, the exhibitors or the general public. Of course, the main organiser for the last 40 years or so, Chris Deith, passed away in May this year which was also a major issue for the organisation. In the event everything went off smoothly with a good response from everyone. The usual features were all there again except that it was slightly smaller than has been seen in the past. There were no major workshop demonstrations, no portable track and a slightly different catering set…

November 19 Cardiff Model Engineering Society Steam-up and Family Day, Heath Park, Cardiff. See www.cardiffmes.co.uk 20 North Wilts MES Public Running, Coate Water Country Park, Swindon 11:00 Dusk. Contact: Ken Parker, 07710 515507 27 North Wilts MES Public Running, Coate Water Country Park, Swindon 11:00 - Dusk. Contact: Ken Parker, 07710 515507 December 1 Cardiff Model Engineering Society Talk: Old Pictures of Cardiff, Heath Park, Cardiff. See www.cardiffmes.co.uk 4 North Wilts MES Public Running, Coate Water Country Park, Swindon 11:00 - Dusk. Contact: Ken Parker, 07710 515507 10 York Model Engineers Evening Talk - 7pm. See www.yorkmodelengineers.co.uk 11 Bradford MES Santa Comes to Northcliff 2022. Northcliff Railway 11:00 - 15:00. Contact: Russ Coppin, 07815 048999 11 Guildford MES SMSEG Open Meeting, Stoke Park,Guildford 14:00 - 17:00. See www.gmes.org.uk 11 North…

Continued from p.635 M.E. 4703, 4 November 2022 Firebox stays Please note that the photographs are examples only and not specific to the Ballaarat boiler. The excess portions of both the firebox and outer wrappers can now be trimmed to the correct length if this has not already been completed. The outer wrapper/barrel will need to have the stay positions accurately marked out, including the four crown stays. The stay holes are to be centre popped and drilled ¼ inch diameter to suit the stays. Deburr the holes and clean up ready for assembly. The firebox/tube bundle should now be arranged so the positions of all the stays can be marked out. The stay positions on the firebox wrapper can be centre popped and drilled about 3mm. Unless you are…

Continued from p.637 M.E. 4703, 4 November 2022 Time to set the Hall sensor This is the method I use, which doesn't mean to say it's the only or best way. This is all part of the final assembly where the heads and manifold with their gaskets are in place and fully tightened down. I would point out here that there are eight of the M2 tapped holes in the side face of the heads that mate with the manifold which, due to the drawing dimensions, break into the push rod clearance holes. This leaves only a thin wall section for the securing cap head screws to fully tighten, so care should be taken with the length of the securing cap screws, making sure they don't protrude into the push…

LNER B1 Continued from p.562 M.E. 4702,21 October 2022 I would now like to get on with the motion brackets and the side platform brackets. First of all, I would like to explain how the motion brackets go together for those who might be a little foxed by this. As you will see, the motion brackets are all in one piece so therefore the expansion links have to be assembled piecemeal. I have to say that this comes from a man who knows about these things as he assembled the ones on the full size A4 so he knows a thing or two about engines! That is to say that the two side plates of the expansion links are inserted into the bearings first of all, and then the radius…