" wrote in
:

On Oct 9, 7:36*am, Doug White wrote:
I am milling a part I want to fit reasonably closely to something
(close slip fit, ideally). *Something like -0.000"/+0.001". *I have
it clamp
ed in
my mill vise, and I have a stop set to locate one end. *I'm milling
out
a
small pocket, and the best I can do for measuring the width & length
is a digital caliper. *The thing it fits on is too big to try in
place.

Thus far, I haven't taken it out of the mill. *I few more passes, and
i
t
should be done. *My question is whether I have a prayer of taking it
ou
t &
returning it with adequate precision if it ends up a bit tight? *I
was figuring that if it doesn't quite fit, I could count on it not
locating exactly the same. *That way another pass with the same
settings should
open
it up a hair.

My experience says that I should (barring chips getting in the way)
be ab
le
to relocate the part within 0.001", but I'm not sure how much better
than that I can count on. *Depth isn't as critical, so a little "vice
lift" won't kill me.

Comments? Suggestions?

Thanks!

Doug White

If you are only making one part and it turns out too tight, then get
out your files and make it fit. If you are making many of the item,
you might invest in DRO for your mill.

I ended up cutting the most critical dimension a mil oversized & filing
it to fit. A DRO doesn't really help here. I can read the dials on my
mill to less than half a mil. Knowing where the table is is only part of
the equation. As it turns out, I ended up cutting the slip fit about 1
mil larger than I'd wanted. This was without moving the piece. I
suspect the problem was flex in the mill. It's an old Clausing 8520, and
although I was taking light climb mill cuts, I'd been taking 5 mils off
per pass quite reliably until I got close. Then I tried to take off 2
mils, and it took off ~ half a mil more than I'd expected per side.

Live and learn. The thing works fine, and I know more than when I
started. All in all, a successful project.

Doug White