"Dave Mundt" wrote in message
...
Greetings and Salutations...

On Sun, 18 Jan 2004 22:01:37 -0800, "Harold & Susan Vordos"
wrote:


"Dave Mundt" wrote in message
.. .
snip---

In a slightly more serious mode...yea...reamers are really
useful. They are the tools that we use to make VERY precise, round
holes in metal.

You apparently have never honed a reamed hole. The typical reamed hole
is
scarcely qualified to be considered precise, let alone VERY precise.
I'll agree that a well reamed hole is drastically improved over the
typical
drilled hole, however. Reamed holes are a distant second to properly
bored holes and aren't even in the running when compared to honed bores.
Reamers are notorious for generating multi-sided holes with bell mouthed
conditions.

Harold


This is true, I have not. my real experience is mostly in the
area of cleaning up morse tapers in lathes, and, sizing mounting
holes through (relatively) thin sheet.
However, I am always interested in learning more subtleties
and tricks to make machining metal easier and better...and I suspected
this thread would cause a few of those to come out from under the
rocks.
More information is better than less!
Regards
Dave Mundt

It's difficult to have some folks understand that reamers are not reliable
where precision is concerned. Many have been lead to believe that they are
the ultimate tool for good finishes and tight tolererance and that simply is
not the case. These are the same folks that would be most likely to argue
the point endlessly, but have had no real world experiences to point out the
weaknesses in reamed holes. It would be easy to draw that conclusion if
all you had at your disposal was a drill press, at which time they would
certainly be better than just drilling.

I've been in the shop since '57 and have seen results from the application
of reamers that are to be admired, and results that would be better
forgotten. When the right speed, feed and lubrication are combined with
the proper amount of stock removed, I've seen holes that turned out quite
well. As I stated, reamers are certainly an improvement over twist
drills, but should be used with caution when it really matters. One of
the very common problems of machine reamers is their ability to yield holes
that are multisided. A reamed hole that has had a pin pushed through it
a time or two, or has been lightly honed, will often display the pattern
readily. While it is relatively minor, it is one of the things that can
lead to part rejection when one works to tight tolerance. It is for that
reason that I speak out. I readily admit that the problems of which I
speak are rarely an issue for the vast majority of the work we all do.

Harold