Got a tuff little job for tomorrow morning...

I'm making a new end of an air cylinder. Start with a 3.5 by 3.5 block
1.5" thick. Center and turn in the lathe so you now have a 2.5" round
protruding 0.25".

Now for the tuff part, turn a groove 0.062" wide on the face right at
the 2.5" round. (This holds rubber ring seal). I've turned a groove on
a face in the lathe before, but never with the protrusion in the way.

I started grinding a little tit on the end of a cutoff HSS tool. I can
see this effort will break right off. I'm thinking to try mangling a
two flute endmill in the morning.

Maybe somebody has a better idea.

Karl