Need knurling information

Feb 16, 2005 3 Replies

I'm refreshing some lawn & garden small engines, and I am wondering if it is possible/adviseable to knurl the pistons on a lathe. I understand it was common practice at one time but has gone out of favor these days. Some of these small engine parts are obscenely expensive. I mean its just for mowing the lawn.



I've been honing out the taper with a rigid hone and the pistons have good grooves but are a little under sized after honing. Just use a regular knurler under the pin hole maybe?? I know it was done with a dedicated machine at one time but a knurl is a knurl huh.? If it goes over sized just knock it back with a file?? Need a special chuck or go with 3/4 jaw??



Been grinding the valves on the lathe using a small router (with the ways covered) fitted into the compound, not as nice as a sioux but the final results are great.



Any advice/comments appreciated.



DE


Pistons are tapered, and the skirts are actually pretty fragile.

I recall seeing a setup in the SB book how they were held in a fixture that the skirt would sit in, and there was a kind of clamp that went thought the wrist pin hole and pulled it down to the fixture plate. I think they had sort of a live center that went over the crown of the piston to help support it.

Jim

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