Hello John

You are correct, in my write up I just mentioned if the builder prefers to use cast iron for the cylinders, then I suggested the use of cast iron rings. I used cast iron on my simplex which has been and still is running since 1976 on my home made cast iron rings with no loss of performance. I put two rings on the piston and made them 1/16"thk. x 3/32" wide and staggered the gaps as pointed out by Jason B to help prevent blow past. Whether having two rings is better than one apart from the blow past as mentioned and having one extra in case one should break, then I would not like to say. Again, I point out the need for an oiling point on the steam chest for giving a dose of oil after running is finished to prevent rusting. I hope this is of help to you.

Cheers Henry

Cast iron on cast iron is the best bearing surface. I had not seen it until I rebuilt a Stuart Turner S9 steam engine, this engine has a 1 1/2" dia piston 3/8" deep, with a 1/4" ring groove, in that I put 2 x 1/8" wide cast iron rings, when fitted the gaps were staggered 180*.

Ian S C

JK – If you struggle to make the rings or to fit them without them braking you could do a lot worse than use packing instead. Its available ont tebay for little money and it is so much easier. I was very wary of this method until I tried it for myself, excellent results!