Charles Vincent wrote in news:yX0Bi.47964$Um6.15150
@newssvr12.news.prodigy.net:

Fortunat1 wrote:

Yes, pucker is a better word for it. the drills are nice and sharp and
I'm getting a good cut there. I've been cutting them out to 7.7 mm and
then reaming to 5/16th. You're right, some of the holes are cut pretty
clean, but the reamer soon produces the rounded pucker as you so aptl
put it.

You are using the reamer to cut .009 inches of material. Generally, I
don't try to do more than .002 to .003. As far as correcting the parts,
you need guidance from someone else. With the metal cold worked like
that, I personally would look closely(with a magnifying glass or an
industrial microscope since I have one) at the edges to see if there are
any tiny cracks. I expect there are.

Oh dear, which means I've just wrecked a whole lot of parts. I'll have a
looksee with a magnifying glass. I did try to cut them out to 7.9 mm, but I
was afraid it might be too deep a cut and that the triangular hole cut by
the drill might leave it's remains around the edges.