On Thu, 17 Jul 2014 19:05:58 -0700, wrote:

On 17 Jul 2014 01:38:01 GMT, "DoN. Nichols"
wrote:

On 2014-07-16, wrote:
I have a couple of Ridgid pipe cutters. They are fine for many cuts in
copper but when cutting thin brass conduits even a slightly blunt
cutting wheel causes problems.

Replacement wheels cost $10+ here.

Questions:
1) Has anybody tried sharpening them? I had a go with a diamond hone
while clamping the wheel on its mandrel in a lathe. The jury is out on
the result.

I would be more tempted to use a toolpost grinder with the
compound set to parallel the sides of the wheel.

2) There are at least two kinds of wheels: Copper and stainless steel.
What is the difference? Would the stainless steel cutter be better for
the thin-walled brass conduit? Will the stainless steel cutter cut
copper but not vice versa?

As in "made for copper" or "looking like copper"? If the
latter, I would suspect that in reality it is simply copper-plated
steel, intended to minimize rust.

If made for use on copper, I would expect it to be sharper, as
the stainless would take more force to cut, and might crush the edge of
a sharp and hard wheel.

I should mention that I use the cutters to cut rings of various
diameters in copper and brass which means quite a few cuts and
consequent expense if the wheels have to be replaced frequently.

Hmm ... the cutter makes for less waste material, compared to
even the thinnest grooving tool.

Do you use it in the lathe, or do you turn it around the
pipe/tubing by hand?

Is it possible to make a toolpost mount for the cutting wheel,
and use it up close to a collet for maximum support.

Thanks.

The wheels that come with the two Ridgid tube cutters (apparently a
"pipe" something bigger), #10 and #20, are F-158 which are designated
to cut "copper, aluminum and brass". You can replace them with a
slightly more expensive E2990 which is designated to cut stainless
steel. If I understand you correctly to use these to cut brass would
not be a good option.

I use these manually although on occasions I have been known to grip
the end of the tubing in a chuck for ease of manipulation.

I have cut the rings on the lathe using a parting tool but that has
its own problems: The bigger the diameter and the thinner the wall of
the pipe the more difficult the procedure. Cutting the brass conduits
this way is impossible.

I wonder how many spare cutting wheels would I be able to buy for the
cost of one tool post grinder :-)

I suspect in the end the thing will be to try a new F-158, E2990 and a
sharpened F-158 side by side and see which performs the best.

Michael Koblic,
Campbell River, BC

BTW asking the staff in the "specialist" plumber shop locally yielded
zero useful information in keeping with previous experience:-)
Greetings Michael,
I've been thinking about your problem and how I would cut lots of
rings from thinwall brass tubing. What I would try is putting a plug
into the tubing so that it could be held tightly in the lathe chuck.
Then I would use an aluminum mandrel held in the tail stock to support
the tubing while cutting. I would make the mandrel about 15 thousandts
of an inch under the ID of the tube. Spin the tubing and apply the
cutting wheel. The tubing must stick out from the chuck enough so that
the tubing can flex against the mandrel when the cutting wheel is
applied. Since the tubing would only need to flex about .0075" you
could cut pretty close to the chuck. I envision a mandrel that extends
into the tubing about 3 or 4 inches. Use some oil on the mandrel. Then
cut off a ring, advance the carriage toward the chuck, cut a ring, and
so on. Then after enough rings are cut to lose the support of the
mandrel, loosen the tailstock and slide it towards the chuck until it
once again supports the tubing. Cutting against the mandrel should
lessen the amount the ring shrinks at the cut, and when the cutting
wheel touches the aluminum mandrel it won't be dulled.
Cheers,
Eric