Easy for you to say...



"Philippe Gravelle" wrote in message
...

"Philippe Gravelle" wrote in message
...


I can only assume the subject says it all.

The only way to repair rusted reamers is to regrind them to a different
size--------unless one can be happy with a tool that doesn't cut well. It's
not something that one can do without a cutter or precision grinder, but
best done on a precision grinder. Even then, the results would be
questionable.

Harold

Harold and Susan Vordos wrote in message
...

"Philippe Gravelle" wrote in message
...


I can only assume the subject says it all.

The only way to repair rusted reamers is to regrind them to a different
size--------unless one can be happy with a tool that doesn't cut well.
It's
not something that one can do without a cutter or precision grinder, but
best done on a precision grinder. Even then, the results would be
questionable.

Harold

Got to disagree I'm afraid. As reamers only cut on the leading edge I don't
find it makes much difference what condition the flutes are in provided
there are no high spots. I've got a selection of old reamers with rust
specks all over them which I get from the local second hand tool shop for a
quid or so each and they all cut fine and to their nominal size. A quick
lick down the flutes with an oilstone to remove any burrs is all any of them
have needed to become perfectly serviceable. The leading edge can be
resharpened as often as you like without altering the size.
--
Dave Baker - Puma Race Engines (www.pumaracing.co.uk)

"Dave Baker" wrote in message
...

Harold and Susan Vordos wrote in message
...

"Philippe Gravelle" wrote in message
...


I can only assume the subject says it all.

The only way to repair rusted reamers is to regrind them to a different
size--------unless one can be happy with a tool that doesn't cut well.
It's
not something that one can do without a cutter or precision grinder, but
best done on a precision grinder. Even then, the results would be
questionable.

Harold

Got to disagree I'm afraid. As reamers only cut on the leading edge I
don't
find it makes much difference what condition the flutes are in provided
there are no high spots. I've got a selection of old reamers with rust
specks all over them which I get from the local second hand tool shop for
a
quid or so each and they all cut fine and to their nominal size. A quick
lick down the flutes with an oilstone to remove any burrs is all any of
them
have needed to become perfectly serviceable. The leading edge can be
resharpened as often as you like without altering the size.
--
Dave Baker - Puma Race Engines (www.pumaracing.co.uk)

There's rust, and then there's rust. There was no information provided so
I responded to the worst case scenario. Can't speak for you, but I've
ground (for size) and sharpened more than my share of reamers in my day and
have a pretty good idea of what it takes to get one to cut size------and not
seize in the hole, or tear it up due to chip welding.

I agree with your comments if the reamer has superficial rust. I totally
disagree if it has more. Notice I didn't say the reamers wouldn't
cut----I simply claim they cease to be a precision tool, such as reamers
are.

Harold

Harold and Susan Vordos wrote in message
...

"Dave Baker" wrote in message
...

Harold and Susan Vordos wrote in message
...

"Philippe Gravelle" wrote in
message
...


I can only assume the subject says it all.

The only way to repair rusted reamers is to regrind them to a
different
size--------unless one can be happy with a tool that doesn't cut well.
It's
not something that one can do without a cutter or precision grinder,
but
best done on a precision grinder. Even then, the results would be
questionable.

Harold

Got to disagree I'm afraid. As reamers only cut on the leading edge I
don't
find it makes much difference what condition the flutes are in provided
there are no high spots. I've got a selection of old reamers with rust
specks all over them which I get from the local second hand tool shop
for
a
quid or so each and they all cut fine and to their nominal size. A quick
lick down the flutes with an oilstone to remove any burrs is all any of
them
have needed to become perfectly serviceable. The leading edge can be
resharpened as often as you like without altering the size.
--
Dave Baker - Puma Race Engines (www.pumaracing.co.uk)

There's rust, and then there's rust. There was no information provided
so
I responded to the worst case scenario. Can't speak for you, but I've
ground (for size) and sharpened more than my share of reamers in my day
and
have a pretty good idea of what it takes to get one to cut size------and
not
seize in the hole, or tear it up due to chip welding.

I agree with your comments if the reamer has superficial rust. I totally

disagree if it has more. Notice I didn't say the reamers wouldn't
cut----I simply claim they cease to be a precision tool, such as reamers
are.

Sure, if the imperfections are bad enough then of course they'll have some
impact on performance but multi flute tooling is very tolerant of
imperfections compared to single point tooling. Even if one flute has a chip
or rust spot somewhere the chances are another flute is going to clean up
the job on its way past. It depends on the type of tolerances the operator
is trying to work to and even quality reamers have a fair tolerance on
cutting size anyway. Tolerance for the smallest reamer is about 3 or 4
tenths and over a thou for bigger ones. Yes you can buy very high precision
reamers, often carbide ones, that are made to closer tolerances than that
but it's unlikely to be of any concern to the average machinist.

As you say though the OP hasn't said what kind of reamers these are or what
he is hoping to do with them so it's all a bit academic at the moment.

"Dave Baker" wrote in message
...

have needed to become perfectly serviceable. The leading edge can be
resharpened as often as you like without altering the size.

This displays quite vividy what you know / as opposed to what you *claim* to
know about tools and the metal working trade over all........

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.

--

SVL

"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

"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,

Okay, I'll buy that--I just miked one and it came in ~ .0005 / in.
backtaper....

When you think about it, a reamer *can't* work properly with no taper--all
you have to do here is consider in theory what would happen if the taper
were reversed....tapered hole and entire flank would drag........

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......

Now the .002 /in number I came up with is something I generally specify when
modifying an endmill for plunge-boring holes as a pre-reaming op....I musta
got that mixed up with standard reamer taper for some reason is all.

Cheers,

--

SVL