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Everything posted by CF MRC

  1. The back of the cab retaining beam has been stiffened and fettled a bit more so the removable roof is now settled down in the correct place. The cab roof has some subtle little eyebrows on the front corners so adding these has also tidied-up this area. The window frames probably need thinning down a bit, but Sir Percivale won’t get the Dennis Healey eyebrows which were later fitted to the King Arthurs. (photo courtesy Derek Pollard) It’s very noticeable that the handrail stanchions and rain strips are quite fine. There are also an awful lot of bolts, but the engines were generally smoother when built. Tim
  2. The cab roof on Sir Percivale has made some progress over the last two days. It is held by a tab at the front and the rear beam, as well as some 2mm diameter 1mm thick rare earth magnets. I may add a few more as they work quite well. The fit will improve when the rear beam is soft soldered to the roof and stiffens the corners where it engages. The rear section slides out and is held by the magnets whilst doing so. The rear beam has some brass brackets silver soldered to it to allow it to be bolted to the roof. I’ll soft solder it on when I’ve made the rain strips. I have some brass right angle strip but I think it’s too small. It begins to look like a Maunsell cab now and should transform the appearance of the engine when re-assembled. Tim
  3. It is very satisfying when you have the correct instrument for the job. The flexibility of my John Stevens watchmakers mill / drill really is invaluable for this sort of work: drilling 1mm diameter for 12BA. The front of the cab roof is held in place with 3x 12BA and 2x 10BA bolts. The 12BA are countersunk and blackened so should hide quite well behind the rain strip. This bit of roof has to be removable when required for maintenance, the rear portion will slide in and out for driving. The roof has a passive fit and so fixings can be quite minimal (no need for multiple 16BAs) Tim
  4. Even though a King Arthur probably never got to Bath, It’s important to get the smokebox dogs right… (the bolts/nuts will be changed - see the ME thread for more info). Tim
  5. I had a very productive day in the garret (small scale) workshop yesterday, but worked far too late into the night. The spectacle plate on Sir Percivale was made from relatively thin brass and so wasn’t very rigid. As suggested by a clever chap on another forum, I therefore soldered together two pieces of 4mm right angle brass section and bent them into the correct curve between fingers and thumbs: Yuri Geller eat your heart out! These were tinned, 12BA-bolted together with the spectacle plate and soldered to the top with a whiff of heat from a blow torch. The whole front end is much more sturdy now. The next job will be to roll the roof from steel with the front section bolted to the T section with probably a string of 16BA bolts. The rear section will be removable for hand access to the controls. Tim
  6. Following from yesterday’s post I have now re-made the front handrail and stanchions on Sir Percivale. The handrail is straight (it’s pivot steel) and slightly longer, whilst the stanchions are more understated. They’re about right now. Tim
  7. The straps have now been screwed / riveted with steel bolts, the ends curved and the finish improved. I have also modified a couple of the (longer) bolt heads with a representation of the nut and bolt. I think the use of a long shouldered bolt will suffice, with this minor visual modification. The two brass handrail knobs will need to be replaced with steel, as these will be in a bright finish. Tim
  8. I returned to the front end yesterday. The smokebox door dogs were originally rectangular in shape whereas they should be more trapezoid in shape. The fixing bolts are 10BA with 12BA heads. Two are long enough with a decent shoulder, but four are too short, so it’s not a matter of if they’re lost but when. I have some 12BA steel hex stock of the right size on order so that will rectify that problem. I can’t think of any clever way to make the bolts captive… The hinge support base also needs re-engineering, but again currently waiting for a tap & due set. The straps themselves are not quite the right shape on the ends, so I will punch out the copper rivets, remove the straps, refinish the ends and polish the steel - but use steel bolts / rivets to re-fix them. Tim
  9. Little bit of extra detail on the rear cab stanchion: it now matches the LHS. Tim
  10. Just like Goldilocks. The first cab stanchion was too thin at the top. The second one two thin at the bottom. The third, just right! (Only 0.1mm difference between them.) Tim
  11. That’s for me to know… Tim (I knew someone would take that bait)
  12. My Australian wife would probably concur… Tim
  13. You could always use some spare etches as a bus garage*, Pete. . Tim (*Stockwell bus garage)
  14. I have been trial fitting the cab sides & spectacle plate. I will have to roll the cab roof, which will be made of steel. For ease of driving, part of the roof will need to be removable. The fixed front section might go as far as the rear of the firebox. The removable section will be retained by a row of rare earth magnets let into the brass. However, I am a bit concerned that the rear ends of the cab roof will be quite vulnerable as they are unsupported. Tying them together with a cross bar might defeat the object of a removable cab roof, but there is a prototypical bar in that area. Any thoughts? Tim
  15. The loco obviously splits into major components which can be sprayed individually. I’m not sure about the boiler: it might be best to take it out for painting with the cladding on: it could then be rotated as it is painted. I would imagine that painting the cladding and then fitting it to the boiler would almost certainly end up damaging the paintwork. The boiler is a good ‘plug fit’ in the smoke box and is removed easily from the frames. The cab spectacle plate is currently far too tight a fit on the cladding and will need easing. There are numerous components that will need to be removed and re-fitted around the cab. I have a small Kite spray gun and used it to re spray the previous A3, Hyperion, and of course the 4” Showman’s RL, Frederick. Lining out will be done directly with a lining pen. Tim
  16. I have fettled the boiler cladding into place this morning. I don’t think that has been done before, as it was catching on the firebox retaining slides. The boiler bands will pull the tapered front sheet into shape. As one would expect, there is a beautifully finished corner beading for the firebox in the cab. Again this needed quite a bit of trimming, but will be a good basis for the false back head that I will make. Tim
  17. Currently settling in the boiler: but these Kelloggs cornflakes boilers will probably not catch on. I have also been working out the plumbing and fittings at the back head: just loosely in place at present. Trying to work out what goes where is quite tricky, but it’s all beginning to make sense. Tim
  18. Engineering artistry, the reversing mechanism made by Ian Jaycroft. https://youtube.com/shorts/fDurgpcnIiU?feature=share Tim
  19. I have started to work on the rear end of Sir Percivale (so to speak) and dismantled the RHS injector. This is more complete than the LHS, including the steam cone. As for the LHS, there is a delivery cone, seen here with a view from the top. There is clearly the central combining cone missing, whilst the relative positions of the other cones can be seen in this ventral view. The steam cone finishes ahead of the water inlet opening (there is a fine spacing washer next to the mating surface with the injector body) whilst the bell opening of the delivery cone can be seen ahead of the overflow. It would be good to get one of the Ian Jaycroft injectors working. It will need the combining cone reverse engineering and a ball and plug for the valve on top. The questions then arising, are: Any idea how to calculate what overall length / taper proportions the combining cone should have? How would the combining cone be stabilised in the middle of the injector body? What size ball for the valve - the hole is 3/32” diameter? How much lift? Maybe I’m expecting a bit much of this: I will definitely use a small Chiverton injector on the other side, when I can source one. Tim
  20. Christmas came early for me, with a successful boiler shell test for Sir Percivale. It wasn’t quite straightforward as there was one internal stay that was weeping under 2x pressure and, needless to say, access was a bit tricky being slightly behind the convexity of the firebox. The original silver solder had inadequately penetrated on the far side of the stay. A couple of hours trying to swage it using a specially made tool, simply rounded off the top. The area was cleaned up using a brand-new, but 50 year-old dental handpiece powered by my equally ancient dental engine, complete with a nasty large inverted cone bur. A front-surfaced mirror, headlight and loupes aided vision. The whole boiler was then gently heated up on a hearth of firebricks and the gas flame concentrated on the outside of the offending stay. Once up to temperature the solder flashed nicely into the joint with plenty of flux, following the heat. I have learnt a lot from this little exercise, with very useful advice from my friends in the North London Society of Model Engineers. Tim
  21. There are a couple of tunnels between Finsbury Park & Barnet. Tim
  22. A great day yesterday when Sir Percivale was connected yup to an air supply and ran. Everything is free running with no discernible slack, the drain cocks work, the exhaust beat is good and I am very happy! https://youtu.be/pLiQy61XpZY Boiler shell test next. Tim
  23. This image was used to make the first scene shown by Simon. We were musing about the likely date for this photo when 10 year old Oliver, on the next door layout, clearly pronounced that it was taken in WW2. When asked why he said that, came the answer, “because the horses are wearing gas masks”. Obvious, really… Tim
  24. The box has now been finished and features wheels that are demountable, being mounted on a wooden stretcher with two 12mm diameter pins locating in steel housings fixed to the box lid itself. These can be removed by taking out the R clips. The reason for being able to take them off is that they would look very ugly when the lid is used to support the diorama section when sat on a table. As mentioned previously, there was always the intention of making mini-scene with an analogue of York Road viaduct. This was tried out with a paper mock up. York Road viaduct had a convenient kink in it, but the diorama version is a very poor relation of the real one when it comes to arches. The shape was roughed in with plywood. This was then clad with Skaters brick plastikard, heavily rubbed down, with enough detail to take the eye into the distance, but not too much. After some Farrow & Ball treatment the bridge and back scene work OK, but there is a huge amount more needed to bring up the perspective finishing between the ground level and vertical painted scene. However, the high viewing angle makes these difficult areas much less visible. The perspective view down York Way works well enough, but it took a bit of experimentation to get the correct angles at the far end. Unusually for me, the sky has no blue in it and the weather has deteriorated over the last few hours. Wembley is definitely getting a downpour. The little car in the far distance is a Z gauge taxi. We also found out today where the MRC gets it’s tea from… Tim
  25. Some interesting recent posts about making. Passing on skills to others is something that is really important for the continuation of the hobby. It is certainly something that I enjoy doing - it’s also the day job in a slightly different context. If someone is keen and intelligent then they will learn how to use their hands for fine work; practical courses such as at Missenden Abbey are invaluable for this. But are we all experts on everything? - of course not. The beauty of the hobby is that you can pick up on the bits that appeal to you: the history, artistry and the engineering are what get me out of bed. As for the other bits, we all have blind spots, or perhaps have jolly good friends who can help. Tim
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