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Bill Darby
 
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Default Dead true centerdrilling.


" Jim Sehr" wrote in message
...
I used to work in a gear shop and had to repair gear shafts that had

been
centerdrilled and had more then the .001 runout that the print called

for.
I used a steadyrest with ball bearing rollers and that gave me dead

true
runout. It is best to collet or chuck on a small part of shaft and let

the
steadyrest pull the shaft to dead true. Then I hand ground a 30 degree
angled tool to form one side of the centered part. Imagine half of a
centerdrill without the drill part in front of the angle. If you blue

up the
center of the part you can see it cut the high point of the runout

till it
is dead on.
Jim

I agree with you. Boring with the use of a steady rest is an
intrinsically accurate operation.