Innholdsfortegnelse for Issue 4713 i Model Engineer

Polly Model Engineering Few of us, I imagine, are unaware that Andy and Jane Clarke have recently retired from Polly Model Engineering and that the supplier has now moved into the care of new management. I would like to wish Jane and Andy a happy and productive retirement, as well as Prof. Pete Thomas, who retired from Polly a little while ago. Pete has sent me a press release detailing the changes to the company, as below. ‘AT Model Engineering Limited is pleased to announce the acquisition of the business and assets of Polly Model Engineering Limited on the retirement of directors Andy and Jayne Clarke. The new business will continue to trade as Polly Model Engineering, from new premises in Cromford Derbyshire. ‘The company will provide a comprehensive range…

ROB ROY RALLY The sun always shines on the Rob Roy Rally. Sadly, last year it illuminated a scene reminiscent of a British Railways locomotive depot in the early 1960s, showing a depleted number of steam engines ‘on shed’. Just three Rob Roys posed on the service line in the morning of September 17th (photo 1). At least they weren't on the scrap line! Many factors may have contributed to the low numbers - the rocketing cost of living and fuel, the recent passing of Her Majesty the Queen and a nearby steam rally all may have been factors. Rob (of brother Roy) was suffering from Covid, as others may have done. Ian Horsfield, of the host club, was of course present with his, as yet, unpainted locomotive. Also from…

HIT AND MISS Continued from p.395 M.E.4712 March 10 A miniature Webster tri-polar oscillator I need castings to work with. For the first batch, I tried a new (to me) material to produce lost plastic castings. It's a product called ‘Polycast’, designed to be 3D printed, then used as you would lost wax patterns. The batch in photo 65 was produced with patterns from this product, using the same burn-out sequence as I use for wax. The only problem is not with the product but with the 3D printing process. The finish on the casting will only be as good as the pattern, as you can see in photo 66. These will do. The worst bits are underneath… Polycast dissolves in alcohol, so the surface can be improved up to…

Introduction I had bought a WM16 milling machine and used it successfully for some time exactly as it was supplied without digital readouts (DROs). I started making a mounting plate for an electrical socket and used coordinate drilling from the leadscrew dials to drill four holes in a rectangle to fit an existing set of holes. I made sure that I compensated for backlash as I moved the table about. When I had finished, I found that one hole was 2mm out in one direction – due to my miscounting the turns of the handwheel. Having mentally kicked myself I decided that, as a significant birthday was coming up, a set of DROs would be a good idea to prevent my repeating the error on other items in the future.…

OSCILLATOR The history of swinging-cylinder engines is a long one. No less an engineer than I.K. Brunel used oscillating machines to power the huge paddle wheels of his Great Eastern (above), while thousands of toy steam models have employed the same principle. Such engines are simple in design, easy to make and will run for long periods with minimal attention. The downside is that the oscillator's efficiency in its usual model form is less than ideal. Indeed, the father of model engineering, Henry Greenly, wrote ‘Advance in the timing of the units is impossible’. The problem is inherent in having the timing of the inlet and exhaust controlled entirely by the side-to-side motion of the cylinder. This is at once the oscilllator's strength and its weakness. Nonetheless, for those planning…

A good working steam locomotive needs to be set up balanced on its axles for best tractive effort, something that I have been working on for my model of 4472 in five-inch gauge. Before building the weighbridge, I studied how locomotives were weighed during the golden era of steam and also spoke to those who have first-hand experience on weighing 4472 (now 60103) in preservation. The full-size weighbridge design as fitted in Doncaster in 1935 was very clever and intricate - far too involved for our purpose but we can cheat with electronics. There are a couple of good images in the book LNER Workshops; Development, Expansion and Demise by Peter Tuffrey. The relevant information is in the ‘Doncaster’ chapter, pages 87-88, where there are two photographs worth study. One…

Introduction Acknowledgements and thanks normally come at the end of a series. For this series I need to break with that tradition and thank Mr. Eric Lander from a small village in Wales for all the invaluable information he sent me (Mr. Lander sent me the name of the village but I would get it all wrong if I tried to type it out here; I thought languages were difficult in my neck of the woods!). Mr. Lander helped me with a great number of pictures of Fire Queen, as it stands in Penrhyn Castle, as well as incredibly detailed sketches of pretty much everything. Mr. Lander also sent me a detailed write-up of the history of the locomotive and a few interesting measurements and facts that disprove some of…

Continued from p.390 M.E.4712 March 10 ALL dimensions are in mm Tolerance for all parts in the article –unless otherwise stated Non-functional (i.e. parts that do not fit all match) ±0.1mm Functional (i.e. parts having to match) ±0.02mm Item 38 – Valve Spool – (fig 56) Ø30 × 4 inch Acetal Holdwith67 protruding. Face off. Centre drill. Support with running centre. Skimoutsidediameter to Ø26 × 66. Setpartingtool with sharp blade protruding 10mm at 90° to lathe axis. Measure11between end face and right-hand side of toolandmake3mmdeep cut (6 on Ø dial). Repeatat52 from end face. Positionleft-handside of tool 40 from end face and make 3mm deep cut ( Removewastebetween the first two grooves until Ø10 achieved – set cross slide dial to 0. Takinglightcuts machine right-hand spool width to 10 ±…

Continued from p.383 M.E.4712 March 10 Astalwart group from the Uckfield Model Railway Club's engineering section, together with a merry peacock accompanist, had just completed the permanent way for a new railway at the nearby Bentley Wildfowl Park and Motor Museum. However, one critical component remained before the first train could be run because, as I understood it, and no matter their size, all railways ultimately need a track on which to run their trains. Uckfield ‘84 September arrived and with it, the date of the club's annual exhibition, a three-day affair and the highlight of its fundraising calendar. Bluebell would be on show, together with her complete but unpainted Caledonian Railway sibling, their first public outing in both cases. This year, in addition to funding the usual club expenses,…

BRIDGET Continued from p.386, M.E.4712 March 10 The dome Of course, the dome is one of the most visually significant parts of most locomotives and this was no exception. The dome came as a gunmetal casting as shown in photo 23. However, I was to discover two quite serious defects in this casting: firstly, the core had not been placed centrally so that on one side the casting wall was 7 mm thick and the other only 3 mm thick; secondly, at some point someone had dropped the casting putting a small but not insignificant dent in the side. Of course, Sod's law applied and the dent was on the thin side of the casting. Given that I had bought the casting second hand and that the seller himself had…

WAGONS Continued from p.401 M.E.4712 March 10 Painting and signwriting The original LSWR wagons were painted brown, obtainable today as S.R. Freight Wagon Brown from Phoenix Paints but only in matt. Running gear and some metalwork was black and the insides were painted ’lead“, which is a bit indeterminate and unavailable as such. For this latter I used an aluminium base wood primer which gives a sort of metallic grey. Paint was all applied by brushing, and then sprayed over with a coat of satin varnish. In my opinion matt paint appears completely dead when used on anything in our scales and the varnish gives the colour a lift and a more realistic finish. It also provides a good surface for applying transfers to; I have found in the past…

March 23 Sutton MEC Afternoon Run from 12 noon. Contact: Paul Harding, 0208 254 9749 26 Bristol SMEE Public running at the Ashton Court Railway BS8 3PX, noon17:00. Contact: secretary@bristolmodelenqineers.co.uk 26 North Wilts MES Public running at the Coate Water Railway, 11:00-17:00. See www.nwmes.info 26 Guildford MES Open day, 14:00-17:00. See www.gmes.org.uk April 1 Bradford MES Annual exhibition and competition, Saltaire Methodist Church, 12:30-16:00. Contact: Russ Coppin, 07815 048999 2 North Wilts MES Public running at the Coate Water Railway, 11:00-17:00. See www.nwmes.info 2 Small Model Steam Engine Group Open meeting. 14:00-17:00. See www.gmes.org.uk 2 Taunton Model Engineers Public running at Vivary track, 14:00. See www.tauntonme.org.uk 4 Taunton Model Engineers Meeting, Stoke St. Mary village hall, 19:30-21:30. See www.tauntonme.org.uk 5 Bradford MES Boating bits and pieces evening, Saltaire Methodist Church,…

Continued from p.393, M.E.4712, March 10 The next thing is, that did you know there are at least six different front bogies on the B1 s and that is without going into all the details of which ones had coil springs and which one had leaf springs! I have given the details in the drawings (figs 51 to 54) of the main differences in the bogies but I have not dealt with the ones which had coil and which had the leaf springs. For that you need to avail yourself of the green RCTS book of the B1 Classes. I am pleased to say that there were only a few which had the coil springs and most of those went on to the A2s, or so I understand. The one…

My third locomotive project has failed its first test dismally, in that it came to grief when mated with the intended load. Not strong enough, it seems, so a bit of beefing up all round should help, plus support where the load is greatest, and possibly a thicker axle. The fundamental principle appears to be okay. In a moment of madness (quiet at the back!) I wondered how two people in mobility scooters might settle their differences. Would there be scooters at dawn? Come to that, there could be races, legal types and open; anything goes. The world speed record is held by two Manx mechanics at over 100 mph. Special category for Zimmer frames? There could be jousting, or 'last to the Ace Cafe is a cissy'. We have…