On Sun, 06 Mar 2011 19:45:40 -0600, Karl Townsend
wrote:

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

The trick here is to grind a tool that looks like a curved parting
tool, with radius of 1.25" on the wide part. The curvature is so the
supporting material under the cutting edge stays within the groove
that the cutting edge makes. The projection would be about .060" thick
(groove width minus a skosh), projecting length need only be slightly
more than the required groove depth. I'd grind it out of a square HSS
tool bit.