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andypugh

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Everything posted by andypugh

  1. Clearly a job for drilling between-centres :-) I guess that drilling and boring one side then mounting that side on an expanding mandrill in the lathe would work.
  2. Lead-free solder + lead-free flux actually works very well on plumbing fittings. But it isn't that good on steel. You can still buy tinmans' solder. (From Cromwell, as an example. And they open Saturday mornings)
  3. https://www.cromwell.co.uk/shop/welding-brazing-and-soldering/flux/fry-baker’s-soldering-fluid-no-3/f/4395?query=bakers%20fluid&brandId=&price=&general=&skip=0&limit=10&categoryId=
  4. I can't answer the question directly, but I do know that my dad's former employer _always_ painted the insides of their gearboxes. I can see good arguments for painting any surface that might rust, and I think that is why gearboxes get painted.
  5. I agree with you up to here. But this seems to be excluding a number of other possibilities. Perhaps it isn't actually mild steel? It would be instructive to do a heat and quench on on un-forged offcut to find out. Perhaps they gave you some EN8 by mistake? It is possible to get brittle fracture of mild steel when the section size is very large[1] and there is a starter-crack. It is just about possible that a combination of a crack in a hard case, a borderline material and a fairly large material section conspired to cause this fracture. I don't see that this can be a "work hardening" problem as I understand the term. I would rather expect it to be possible to bend the material into shape shown by cold-forming without fracture, if it was possible to apply the loads required to achieve that. It isn't a very large shape change. I know much less about deformation in hot metal than I do about cold metal. I would be interested to learn what the issues are with hot forging at too low a temperature. I would anticipate that there is likely to be problems with weakening grain boundaries that are not then re-formed on transformation. [1] https://en.wikipedia.org/wiki/Fracture_toughness is sensitive to geometry. In applications such as pressure vessels with very large wall thicknesses it is necessary to perform tests with specimens of a similar scale to the proposed wall thickness. This can require some truly enormous tensile testing machines because you can't simply use a lab-scale specimen and multiply the numbers. AEA Risley had a machine capable of testing 500mm wide CTS specimens.
  6. I respectfully disagree. That's a brittle fracture due to quench-hardening. I am not sure if it is actually due to accidental case-hardening in the coke, you would normally have to actually try to get a significant case depth, or whether the steel used actually has a reasonably high carbon-equivalent content. Do you know the actual steel grade, Steve? You would need a lot more strain (shape change) than that for significant work hardening, but I am actually basing this opinion on the colour of the fracture surface. (In a previous life my job revolved around heat-treatment, cold-work and fracture mechanics research)
  7. You will need a little bit of backlash allowance too, though time and miles in the meshing gear might have added plenty of that.
  8. Quite a lot of Sankey wheels in that photo, but I only know of one set in preservation, and that on a vehicle that has basically never been off the road. I wonder if they cope badly with being left in fields or under houses?
  9. Our JCB (3CX) had an interesting arrangement. It had the normal split and bolt, but in the split was a fat washer round the bolt that fitted into a Woodruff slot. Rather neat, really.
  10. https://www.coventry-grinders.co.uk/product/imperial-gauge-plate/ Lists 1/4" x 1/4" gauge plate 18" long, 36" on request.
  11. I feel sure that it would take more than human strength to break that bond. I found something on the internet saying "up to 135,000 psi in shear" so lets assume half that in this case. Area is about 7 square inches, so that is 500,000 psi. at a radius of 0.0625 feet. So 30,000 lbs-ft of torque capacity. The shear are of the steel key is much less, I reckon that would fail before the silver solder.
  12. Design Spec: 1) Useful to drive a tank while looking through. 2) Bulletproof
  13. An encoder on the spindle and a stepper motor on the leadscrew is possibly easier, and more adaptable. And, also, cheaper. Or a full CNC conversion :-)
  14. I would go with "speedometer" too. There might even be a skew-drive out the side for the cable? Speedo drives were much chunkier back then, even on motorcycles: http://s947.photobucket.com/user/1953Indian/media/Ner%20A%20Car%20with%20speedometer%20A.jpg.html
  15. A vaguely similar machine is still in productive use with Keith Fenner: (You can see the full majesty of the flat-belts at 23 minutes in)
  16. Have you also remembered that the steering drop-arm needs a pinch bolt?
  17. Wow! Is that load bed original? That might be the only one left...
  18. A bit of pipe insulation with pipe inside it (and probably parcel tape) would probably make a perfectly adequate core. Make the plug, make a negative of the plug as the core box with an oversize cavity. Make a core to sit in the plug with spacers, fill in the gap with more resin/expanding foam to shrink the core box cavity. There are some very interesting techniques here:
  19. Also note the variant and more common spelling "Thackery"
  20. I think that crushing the 16mm size in a press to put the kink in might get close enough. The alternative would be to mill them from solid. How many do you need? (I have a mill with a CNC rotary axis)
  21. It does look like one saw-cut, a 180-degree rotation and welding it back together would give you the shape you need. I think I would be looking to make the saw-cut in 3D CAD first, though. In fact, I just did (with guessed measurements)
  22. It looks like one flange per pot. Why not make some short bits of tube with a flange on each end to bolt to the head, and then bolt the castings on top of those? Though I imagine the original was a long sloping pipe? That wouldn't be desperately hard to make from scratch by welding. Dennis seemed to like to use large-bore copper pipe and brass flanges soldered on.
  23. A pair of these? http://www.demon-tweeks.co.uk/motorsport/universal-elbows/samco-90-degree-silicone-hose-elbow-2 (available in black, it's not a 100% jocular suggestion)
  24. What a marvellous device. I have a vehicle with exactly that drive system already, and it works almost adequately. I won't be adding the Lambert to the collection at that price, though. (seems overpriced, too)
  25. I wonder how many JKBs worked at Mirrlees? There is a sectioned engine at Bovington, but you presumably know that. It appears to be a rather unusual crosshead type engine. Do you know if the area under the piston had a function as a pump or anything?
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