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.

OK, looked at the holes using s 10X microscope and they're not exactly
mirror finished, but they don't look too bad for the most part. I didn't
find any cracks, but I did find some microscopic chatter marks, scrapes and
chips along the edges. Also found a couple of gouges that ran across the
holes from edge to edge that could best be described as a "step".
None of these imperfections were deeper than say, .002, if even that deep.
I do have my "guy" comong over to have a look, but from my description on
the phone he thinks they're probably OK.
It's all learning, eh?