"Bob May" wrote in message
...
I'd probably take the collet to an auto machine shop and have them hone it
to the desired size with an abrasive hone. You'll want to put the collet
in
a holder and put some brass in the slots so that it doesn't compress.

Actually, I was referring to a solid end mill holder, not an R8 collet. Not
that I have anything against R8 collets, it's just that I don't think a
collet would be a good choice for this particular application.

But it might not be a bad idea to take the 1" end mill holder to an auto
machine shop for honing to 26mm.

- Michael