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.
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?
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.
I would be more tempted to use a toolpost grinder with the compound set to parallel the sides of the wheel.
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.
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.
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:-)
The last time I had to cut a large quantity of thin wall brass tubing I used a jewelers slitting saw in an arbor chucked up in the lathe spindle. I removed the tool post, drilled a piece of steel to accept the tubing diameter mounted it on the compound and used the power feed to advance the tubing into the saw blade. After the setup was fine tuned (feed and spindle speed.) I cut thousands of those parts within .001" length using only one .005" thick saw blade. Jewelers saw blades are inexpensive and available on ebay. If you want to get fancy you could use a 5C collet block and you will reduce or eliminate marks on the tubing OD.
I don't know for sure, but I would expect them to have a less sharp edge, and to be a tougher alloy. Those for copper, aluminum, and brass I would expect to be harder, and sharper.
But -- these are only what I *expect* -- not what I know from any studies.
Maybe someone else knows for sure.
Hmm ... I'm presuming a 3-jaw chuck. A 6-jaw would do better on thin material, as it supports the material a lot closer together.
What are the diameters involved? Holding them in a collet (up to 1" if you can use 5C collets, smaller with 3C collets, and I don't know what collets might fit your lathe -- if any. There are larger ones as well, but I doubt that you have that big a machine.
I seem to associate you with a small import lathe, so 5C collets are probably not an option.
Now -- if you have chucks (even 3-jaw chucks) with top jaws, you can make soft jaws (from aluminum would be the easiest choice), and shape them so the jaws almost contact each other. You then bore a set to fit a particular size of tubing, and it gives you a *lot* better support all the way around the tube -- and less chance of maring the tubing itself, too.
Let's see --- $10.00 each you said above, and you can sometimes get toolpost grinders used at quite reasonable prices -- say $140.00 or so.
Or -- you could do a bit of work to adapt a Dremel tool to your toolpost, and use it as the grinder.
Or -- if you have compressed air, it would be easier to start with one of the pencil style die grinders driven by compressed air (a lot smaller at the toolpost) and use it.
O.K.
It might also be possible for you to make your own wheels from something like air hardening drill rod -- especially if you set up to sharpen them with your makeshift (or a real) toolpost grinder.
Of course. They don't think in terms of resharpening tools, or using them on materials other than the labels say they are for.
Why not just sharpen the cutter wheels? I've been doing it for years. I use a nail that fits the hole in the cutter and a short piece of tubing that slides down the nail and keeps the rotating cutter from skidding off. Hold the edge of the cutter against the side of a grinding wheel at the correct angle to grind the bevel you want and the grinding wheel will both rotate the cutter and also grind it. Flip it over and grind the other side. If you've got the correct size nail the whole exercise takes, maybe 5 minutes.
A finer finish can be accomplished by using a finer grinding wheel.
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
Interesting. Have you used it yourself? I read all the reviews and even some of the 5-star ones made me wonder. Would it mangle a brass conduit with 0.030" walls?
You have hit the core of the problem which is the deformation of a thin-walled conduit while cutting. Following on from your thoughts I suspect I should get much better results even using a hand cutter if I put a mandrel through the conduit first. Maybe even a wooden one.
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Horse-pucky. Unless you're so ham-handed that you gouge the edges 20-30- thou, the WORST it will do is cut a _slightly_ crooked cut. "Threading" is caused by loose bushings in the wheel and the rollers. If the wheel and the rollers roll 'true', it cannot help but cut true, so long as the sheer edge of the wheel can find the old groove.
You can cut true with a wheel that's five or six thousanths out-of-plane, and anybody with reasonable eye-hand coordination can do that on a common grinder, by hand.
You don't just take the wheel off and try to hand-hold it! You put it on a spindle (bolt, turned rod, whatever), and admit it to the side of the wheel such that the angle of incidence doesn't spin it real fast -- just a hundred or two RPMs. It's self-equalizing that way, and you'd be a real klutz if you couldn't get it nice and evenly tapered that way.
And it takes more time to remove and replace the wheel from the pipe cutter than it does to touch up the edge.
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ALWAYS use a close-fitting mandrel when cutting thinwall _anything_.
'Rule of thumb'
Besides, do you want to then have to chamfer the i.d.? I use the closest-fit I can get, and hard enough material so that the pipe cutter won't cut into the mandrel. I can always re-sharpen the wheel, but sometimes it's tough to get a short piece of tubing off a mandrel where the tube has been swaged into the groove in the mandrel.
I've used mine as intended, on steel tubing and exhaust pipes where it works well enough. I suspect it would crimp thin brass no less than a single-wheel cutter does.
I chuck brass tubing in a collet and part it with the thinned back end of a cutoff blade. Before buying the lathe I cut it with a razor saw.
I just ordered one of these to try on thin sheet metal, specifically the trim from an above-ground swimming pool.
I discovered this little fact probably as you were writing about it. I grabbed the first piece of wood I could find which was a pick-axe handle. I put the brass conduit as far as I could on the handle taper which turned out to be too far. I cut a nice ring and now I have two pieces of pretty brass decoration as neither piece will come off due to the phenomenon you described.
I cut a second conduit lower down on the handle with a good result.
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!!!
Heh! I like to use a mild steel or annealed stainless steel mandrel for cutting thinwalled tubing. It doesn't injure the wheel (much), but gives some positive feedback when you finally cut through.
Greetings Michael, The reason I suggested a slightly undersized mandrel is because the ID of the tubing will shrink some. But the other important feature of the setup I suggested is that it limits the deformation because only one cutter is used. This is because the tubing is supported right at the pressure point. If more than one cutting wheel is used the tubing will not be supported at every pressure point and so will shrink. Cheers, Eric
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Eric, if the mandrel is a very close (nay, 'snug') fit in the tubing, you'll get no noticable distortion of the diameter, regardless of how many wheels are on the cutter.
If the mandrel fits well, only one is required, ever.
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