MAKING PISTON RINGS

We often get to a stage on a restoration of an old engine, be it steam, oil or a model, where we cannot go any further without new piston rings.

These are often unprocurable or involve a long wait and expense getting some specially made. However, if you are handy with a lathe they can often be made simply at home; the basis of the method is to turn the rings cylindrical and then stress relieving them to the correct shape. Here is the way I did it for a model engine I got as a basket case.

How they work

This is fairly obvious; it is to make a gas tight seal between the piston and its cylinder. A secondary function can be wiping excess oil off of the cylinder walls. One approach to achieving a good seal could be making the piston a perfect fit and not use rings, but this is generally not practical as the clearance