FILL IT TO THE TOP
If you have a piston with a dome volume, you’re unsure of, here’s an easy way to check. Wrap a single layer of thick packing tape around the head land, taller than the dome. It will maintain the full round shape if you’re careful. Fill it to the tip of the measured dome height and note the burette volume. Deduct that from the calculated volume of your crown diameter and dome height, and that’s your approximate dome volume. It’s not going to be an exact due to the surface tension of the fluid, but you’ll have a very good idea what you’re dealing with. I get within 1/2cc of the published dome volumes checking this way.

Ron Flood
Cedar Machine
North Branch, MN
JUNE, 2022