"Robin S." wrote in message
m...

"Jeffrey Lindemuth" wrote in message
...
I am going to use a tool post grinder on my 9 inch star lathe. I picked
up
a
Dunmore #14 at an auction recently. It is small, but taking lite passes
and
grinding between centers, I think think it will be OK. This is a hobby
project, time is not a major concern.
For lapping, I am planning to use cast iron laps and lap on the lathe,
as
described in modern toolmaking methods (1915).
Just seems like a neat project.

If you set your compound rest to 6º clockwise past the z-axis (that is,
almost parallel with the ways the carriage slides on), each graduation on
the compound turns into a movement of 1/10 of the grad in the x-axis.

This means that if you dial in .001" on the compound rest, you will reduce
the *diameter* of the work piece by .0002".

Yes, for all of you with calculators it's actually something like 5.75º
but
you don't need to be that picky.

I've had to turn (with a HSS cutter) 12L14 to a tolerance of +/-.008mm and
this method works quite well.

HTH.

Regards,

Robin


Yeah, it works quite well until you have to rely on stops or marks such as
when approaching shoulders. Movement of the compound causes you to lose
location. It's far better to learn to work with the cross slide instead.
Yes, it is difficult, but certainly not impossible. I've done .0002"
tolerance work that way for years with good results.

Harold