PrecisionMachinisT wrote:

"Harold and Susan Vordos" wrote in message
...

"PrecisionMachinisT" wrote in message
...
snip-

Any chucking reamer has an inherent back taper designed and ground about
the
diameter....generally its ~.002 / inch--and as such, they certainly *do*
lose a bit of diameter *each and every* time that you re-sharpen them.


While chucking reamers do have taper as you suggest, it is much more
gentle.
Typically, a small chucking reamer (3/8", for example) would have about a
half thou taper in it's entire flute length.

You can usually tell if a reamer has been reground by checking the shank,
between the flutes and the area used to grip the reamer. Taper for the
flutes is generally set there before grinding a reamer to resize it. That
way one can alter the size of a reamer by tenths with no risk of ruining
its
size while making the proper setup. As I said, I've reground a large
number of reamers in my day, and that's the process I was taught to use by
my mentor, who had spent his life time in the grinding room.

Because chucking reamers cut on the chamfer, Dave is somewhat right in
that
you can sharpen them time and again and not lose size, but you're limited
by
the center hole on the cutting end. As you repeatedly sharpen them, you
run into it, so you have to lose the center hole---but by then you
generally
are satisfied that the reamer cuts the desired size, so it's no big loss.


Harold,

..............................
Mainly I saw the opportunity to harass Dave a bit and just *couldnt resist*
the temptation......my main point being that size is *definately* changed on
sharpening a reamer--not much.....but still it *does* change, this being
contrary to his claim......
..........................

Cheers,

--

SVL

If what you is true, there would be no point in sharpening reamers,
fortunately it isn't, machine reamer manufacturers cylindrically
grind the lands of the reamer to the true size for a distance,upwards
of .32", depending on diameter, adjacent to the bevel cutting edge.
That way the reamer can be sharpened a number of times before the
sharpening process incroachs on the back taper ground section of
the body. This "true" diameter also acts as guide & pilot for keeping
the hole in line..

Tom