SpudFiles

Can I make the grooves for the check valve effect with a dremel.

Why not?

I didn't know if a dremel was powerful enough to make the grooves.

If you're talking about for your piston, then you'll need a strong bit to do it. I made mine with a bench grinder. You can use a file, or hacksaw, or anything. Just clean it up so it won't cut the o-ring.

Coulda posted this in your piston thread...

You could also use a sharp pair of tin snips, or something like them.

FYI: If this is related to your piston, you should have posted this in your piston thread.

I can merge the topics if you wish but next time you want to ask a question related to a topic you have already started, ask it in that topic.