"Robin S." wrote in message
...
snip---


Your right in that there is a possibility that none of the suggestions in
this thread have correctly addressed the original poster's question.

I don't know that it is his right, or not. That he is correct, or not, is
another issue. Did you mean *you're* right?

Grasshopper, I take exception to your implication that none of the
suggestions have correctly addressed the OP's question. My response to him
not only addressed his situation perfectly, but is the method of choice by
those of us that know and understand how to operate a milling machine, and
have used that very process for the duration of our machining careers. Any
lesser method leaves questions as to actual location of the spindle as it
relates to the hole.

He asked, clearly,

"I'm locating the center of some holes .500" dia with a Starrett edge
finder.
The tip of the edge finder is .200. I'm just not sure if I'm doing it the
BEST way."

Of course, that is not the "best" way. Edge finders work great for
locating from straight cut edges, but not so great from holes. Lets not
go where we begin the argument that if you do this and this first, they work
fine. That's not how they're intended to be used, so I'm not interested
in the discussion. The *best* way is to use a dial test indicator, full
stop. The level of precision is in keeping with the most rigid of
requirements and requires no particular knowledge or skill. It also does
not rely on any "Kentucky windage" for interpretation the way picking up a
hole does with pins.

This is a perfect example of "one way is superior to all other ways."

Harold