thanks BOBCRMAN,
for Goodsons site. there is sure as lot of interesting reading ahead for me there.

That VW industrial motor asks for a 45 + 15 + 75 degree angles on the valve seat.
The factory manual mentions a cutter to do the job. Does that mean a different tool than the grinding stones or is a cutter what the "stones" are called.
I sent a email to SnapOn asking for a copy of the operation manuals for the valve tools.

Is our SnapOn valve seat tool made by SnapOn or do they slap their name on it?

Any suggestions on books to learn the tools operation-
thanks for your time
hank