Wednesday, October 22, 2014

Bushed chassis

I'm not sure what world Nu-Cast were operating in when they decided that the whitemetal loco chassis would provide adequate bearing surfaces, but in my world they were wrong.
With all those waggly bits hanging on the outside, I really don't want to have to strip the mechanicals down just because after a prolonged period of running, the axle holes are the shape of a Wheetabix rather than round.
So, after digging four brass bearings out of the pot you saw yesterday, I reamed out the holes in the alloy lump and glued the metal bits in place. Reaming took rather longer than I expected as the hole enlargement is greater than I expected but once done and with the holes countersunk, the bearings were pushed in to place and then pressed home in a vice. Only one needed a smear of runny superglue too.

1 comment: said...

People often worry about white metal as a bearing surface, but in fact that is one of its chief uses. In car engines, the bearing between the crankshaft and the connecting rod is of white metal. Railway vehicles with plain bearings (i.e.not roller bearings)had these made out of white metal. It wouldd be interesting to hear if anyone has a white metal power unit that has in fact worn out. Misaligned bearings through the vagaries of the casting process are another matter..

Chris Thomas