Hi all:-
What's the typical procedure used to establish a datum when using a DRO on a mill?
I suppose if you have a hole to indicate you simply locate the quill over the hole and reset the X & Y axis to zero.
What about using an edge finder? Run it in to the edge and preset the axis to the radius of the edge finder (taking sign into account)?
How about on a lathe?
Seems simple, but I want to make sure I'm not missing anything.
Best regards, Spehro Pefhany
I use an edge finder (as you describe) both for edges and for holes
1/2" dia or greater. For holes I use the technique described in one of Guy Lautard's Machinist's Bedside Readers: eyeball it to close, locate the sides in X center in X, locate the sides in Y and center in Y, repeat the cycle. That gets me within a thou which is as close as I ever mill anything. Takes longer to type it than to do it.For smaller holes I use an edge finder with a conical tip, but without the spindle turning. Lower the quill so the cone seats in the hole, then adjust X and Y while feeling the edgefinder with my fingernail. That also gets me within a thou.
Any particular reason that you don't sweep the hole with a dial indicator? BTW,I occasionally do it your way. Randy
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