Denis....not to worry,

....deglazing stones are 180 grit, and are used in electric drill motors. Once you
have cleaned and scratched the surface, like I have shown in the picture, you
are done. The cylinder is made of very tough material, you cannot hurt it.

You could use 400, or 600, or 800, or 1,000, or 20 million grit paper to
"deglaze" your cylinder....every time you go to a finer grit, you will spend
more time trying to get the ring to seal.

Don't believe me ? Find out for yourself.

FBD.