Sunday, January 07, 2007

Coupling Rods


rods
Originally uploaded by Phil_Parker.
Con rods are usually a fairly pain free part of a build – right up until you try and fit them.

These were simply a case of laminating two etchings. I tinned both first. Then flux was smeared in between them as they were held together with wooden tongs. Soldering along the edges made the solder in the middle run nicely to hold the parts together.

The holes for the crank pins were then reamed out. I don’t worry too much about accuracy of alignment of the parts because as long as they look OK, this step sorts everything out.

The holes in the rods should be the same distance apart as the axle holes. If not, the loco won’t run. These were wrong by about a millimetre. Not huge but bad enough. Hopefully some elongation of the holes will sort things. If not I’ll have to separate the etches and look at shortening them.

This is why the loco has to be test built. This sort of thing can be correct – possibly with some milled rods – but you need to know about it first.

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