Lapping piston rings

[Ed Wright]

Originally Posted by George Wright

I had this tool made up about 25 years ago. It is for a 4.060 bore. On one side there is a dish cut in it that allows you to hold a ring inside of it. The ridge is about .025 tall so that the ring is exposed. I can then use this fixture to sand down the ring on a piece of fine paper taped to a piece of glass. The other side of this ring fixture is used for squaring rings in bores when checking / setting the ring end gaps.

Mine look just like that, but a little deeper. .035" for the old .043" rings I was using.
And, no the rings stayed in place just fine.
Lap one side flat, flip them over and lap the other side flat. Mic the ring, and if needed, touch up the thickness.