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I'm working on a project which includes a copper bushing (made of 3/8" OD copper tubing--the walls of which are somewhere around 1/16"), and am considering how to batch out these parts. The approach I'd like to take is to create a wider blank, with the bushing installed--then to resaw the blank into several individual pieces.

I'd prefer to do this on my bandsaw, which currently has a ~6tpi blade. Would cutting the copper tubing be likely to damage the blade, or destroy the workpiece (excessive tearout, etc)? I've cut aluminum on my circular wood blades before, but never the bandsaw--and understand pure aluminum is softer than copper.

PS) For a little more context, I'm making keychains. Here's a prototype--it's approximately 3" long and 1/2" thick. If you have other ideas about how to produce these please add a comment!

Keychain prototype with copper bushing

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    I did a similar thing and cut some copper tubing thing for a decorative element on a project, and I cut it with a tube cutter like this one (not a sales recommendation, just an example). It dimpled in a tad, and I had to ream it back into roundness. I also filed sharp edges; any method of cutting it will leave these to a degree. I used the same cheap round files I got from (I think) Harbor Freight for this. The metal is soft enough that it worked fine. May 2, 2022 at 13:55
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    If I were doing it again, I would insert a snugly fitting dowel into the copper tube so the cutter didn't flare the tubing so much. In fact, I might have done that, it's been awhile and I don't remember anymore. A metal rod would be even better, as it wouldn't compress as much as wood does. May 2, 2022 at 14:00
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    Cutting metal will dull any blade faster than cutting wood does. I've accidentally cut a 1" long nick into a cast iron table saw top with a circular saw and a carbide tipped blade (sparks flew, 1/10 do not recommend), and the blade made it through apparently no worse for wear. So I personally wouldn't hesitate to do this on my band saw. But your tolerance for blades dulling may be less than mine. I personally consider it within the expected wear and tear on a blade. I don't do that many projects a year, which probably informs my tolerance. May 2, 2022 at 14:07
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    It will depend on the alloy and hardness of the saw blade. High speed steels will cut copper all day ; the band saw blade is very unlikely to be HSS. An inexpensive carbon steel will cut but would soften from heating. So cur slowly to minimize temperature of the saw teeth. May 2, 2022 at 14:22
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    I think you should use epoxy or PU glue on production pieces. Much stronger, but also will give u much longer working time :)
    – Volfram K
    May 5, 2022 at 5:46

4 Answers 4

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Would cutting the copper tubing be likely to damage the blade

I doubt it since copper is one of the softest metals going, and bandsaw blades of spring-temper steel are already regularly used to saw metals, including aluminium alloys that are much harder than straight aluminium.

Obviously you'll want to test this once or twice and gauge how the cut goes with your blade, but the above should at least indicate that it's not a crazy notion and that excessive wear to the steel shouldn't be a particular worry — in fact some woods would be far more wearing due to their silica content, silica being significantly harder than copper (7 on the mohs scale versus ~3).

That said, I'd prefer to do this with a blade with much smaller teeth than on a 6TPI but it should still be possible.

  • First off, make sure your bandsaw is well adjusted before you start (good guide to this from Stumpy Nubs).
  • Bring the table up so there's minimal blade exposure (to increase support and reduce vibration).
  • Run the saw faster rather than slower.
  • Feed slowly for the same reason as the above — so that as many teeth as possible are involved in the cut.
  • If you're batching out a large number don't do too many cuts sequentially in case this might overheat the blade.

If you want to take an extra precaution and ensure the pipe is as soft as it could be you can quite easily anneal it1 but you'll have to abrade it inside and out to restore the bright finish. This is very quick work with modern abrasives, but dusty.

Pipe cutter?
You could of course use a pipe cutter to cut your little pipe segments, but they're not made to produce visually neat cut ends..... they only have to be good enough to work inside a pipe fitting of some kind where they're hidden from sight forever :-)

If you try to batch out correctly sized copper inserts with a pipe cutter you'll hate yourself, trust me2. If you do end up choosing to make yours this way I would deliberately cut them overlong, planning to sand off the excess from both faces once glued in and the glue has fully cured.


Deburring
Do make sure to factor in the time this will take into your calculations. Regardless of the method used to cut the pipe you'll have to deburr at least the inside of the tubing; there may not be much to choose between methods in this respect, especially with post-cut sanding added into the mix.


1 Heat to a dull red, then cool any way you like — there's no quench-hardening in copper, so you can plunge it directly into cold pickling solution if you want to proceed quickly. This has the advantage of flaking off quite a bit of the oxide skin that forms, saving you having to remove it in the next step.

2 I have to make a few copper ferrules infrequently but regularly for tool handles and even with that relatively small number doing this with a pipe cutter is the only part of the whole job that I dread. Even the tedious and sometimes tricky drilling out of the centre of the handle is less onerous.

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    +1 Agreed that I'd be worried about damaging a 6TPI woodworking blade, though, to be honest - especially if it's in good condition and is used on other reasonably fine woodwork projects. The cost of a cheap 14TPI bimetal/HSS blade and the two minutes it takes to swap is sensible insurance - especially if the woodwork blade is on the expensive side.
    – J...
    May 3, 2022 at 20:45
  • Thanks! I realized my current blade is probably getting close to retirement, so I might order a replacement and sacrifice the current one to test cutting copper. I hadn't considered annealing the copper but might try that as well--and perhaps should also try using a thin kerf blade on my miter saw rather than the bandsaw.
    – STW
    May 4, 2022 at 13:39
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    Because copper is so soft, I'd worry about the sawing distorting the ring. I'd suggest at least trying to friction-fit a piece of wooden dowel inside the copper. And epoxying the tube in place before cutting is also a good idea. May 21, 2022 at 2:03
  • @WhatRoughBeast, this methodology is to cut the assembled 'master piece' into strips so the idea is that the pipe would be epoxied in place already. Unfortunately a close-fitting dowel to support the pipe is a problematical idea since if there's galling in the direction of the cut, or even the slightest distortion, it may subsequently be extremely difficult to remove the wood (bearing in mind that except for final part #1 and the last one both ends are cut, effectively trapping the dowel segment). I've experienced this on a very small scale cutting ferrules with a hacksaw and, well <shudder>
    – Graphus
    May 21, 2022 at 16:33
  • @Graphus - I will, of course, bow to actual experience. I figured a dowel would act like a zero-clearance insert on a table saw, and reduce galling (tearout). And yes, I recognized that getting the dowel out might be a problem, but I figured it would be worth a try. At the very least, I'd try making a close-fitting hole in a piece of scrap, then using that keep the copper in the hole while pulling (or pushing?) the dowel out through it. May 22, 2022 at 19:38
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The carbide tipped blade on my Skilsaw slices through ten penny nails like they were butter. I would consider using a radial arm or chop saw with such a blade.

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    I might try this--I've cut aluminum on my miter saw and it does a great job. Maybe I'll put on an older blade and do some test cuts. The circular blade with carbide teeth does seem like a better option than the bandsaw blade for making the cut and leaving a better finish.
    – STW
    May 3, 2022 at 14:58
  • +1, more wood lost to kerf but maybe worth it.
    – Volfram K
    May 4, 2022 at 9:10
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Cutting metal with bandsaw blade and blade speed designed for cutting wood will ruin the blade very quickly (unless you've got a carbide resaw blade, but even then, I wouldn't do it - those are expensive blades, and there is no doubt you'd be degrading the wood cutting edge of the blade cutting hardened, unannealed copper). That said, there are obviously blades made for bandsaws that are hardened and designed to cut metal. You could use such a blade - it'll cut the plywood just fine, although you might have trouble with the blades becoming overloaded with fine chips, leading to poor cutting and burning, particularly since your wood bandsaw will be running the metal cutting blade significantly over its design speed.

But what I would do if I were building your design, is to cut the bushed end of the piece in a vice with a hacksaw, then flip the piece over and make the rest of the cut on the bandsaw. Unless you're making hundreds of these, that'd be easier and faster than setting up the bandsaw with a different blade. A sharp, 12tpi hacksaw will cut through the bush end quickly and accurately.

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  • Ahh yeah, good call--the blade on the bandsaw I was thinking of when I left the comment above is, in fact, a carbide tipped resaw blade. Resawing is primarily what I use the bandsaw for, so that's the normal setup for me. Important caveat to my "I wouldn't hesitate" comment above. May 2, 2022 at 14:28
  • Good idea on doing a separate cut with a hacksaw--I'll give that a try. Thanks!
    – STW
    May 2, 2022 at 14:33
  • Carbide can cut steel with zero damage! Very frequent occurance on table saw. +1 for using hacksaw and bandsaw for parts of cut.
    – Volfram K
    May 4, 2022 at 9:09
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While it would be more convenient to cut the tubing and wood all in one go, there are a couple of issues:

  1. It may be difficult to get the tube through all the blanks in one shot, especially if it's a very snug fit. Getting a 1/2" in piece in is one thing. Getting a 12" piece in is a whole 'nuther matter.
  2. 6 TPI will make a nasty cut in the metal.
    • Just like cutting wood, the more teeth, the smoother the cut will be. Any metal cutting tool you see will have a lot of teeth (except for a demolition blade for a Sawzall™-type saw, because it doesn't matter).
    • The more teeth, the slower the cut in wood will be.
  3. The comments well address the damage you'll likely end up doing to a blade designed for wood, and a metal-cutting band saw blade will probably not do a very good job of cutting wood.

I'd suggest a standard plumber's pipe cutter to cut the tubing:

Standard screw-type pipe cutter
image courtesy of lowes.com. No endorsement intended or implied

It should give you a nice clean cut with very little roughness to clean up before installing the pieces into the wood. It doesn't take long at all to cut through copper plumbing pipe by hand (I've done a fair bit of it, it does go quickly), then a couple of swipes with some emery cloth (or even just sandpaper) to smooth off any burrs and ensure it's smooth enough for hands and pants pockets and you're ready to go.

I've never had one dimple or otherwise damage the pipe, so there should be no need to put anything into the pipe to support it. Don't forget, plumbers use these for cutting pipe all day long all around the world - they don't back the pipe with anything, and even a slight dimple would leave them with leaking joints, so it shouldn't be a problem.

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  • Thanks! I actually did use a tubing cutter to cut to an approximately length, and it works great for that--but removing the excess to make it flush was relatively slow. Using it to cut more precisely hasn't worked so far--but perhaps I could build a jig to act as a stop block to help make consistent and repeatable cuts with it.
    – STW
    May 2, 2022 at 15:34
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    ...one detail I'd disagree with. Tubing cutters do taper the tube a bit--or dimple it if it's advanced too quickly. Plumbers don't need the ID to remain perfect, since they solder the tube into a coupler that overlaps it by about 1/2" or more and the taper is usually just about 1/16". In my application the tapering would need to be addressed--either by preventing it, flaring it back to the original OD, or cutting the tube proud before removing the taperered portion by sanding or another means.
    – STW
    May 2, 2022 at 15:43
  • If there's dimpling, I never noticed it. I would think that once the sections of tube were glued in place in the wood, a steel rod, passed through the tube and held at an angle so it was at 12 o'clock on one side of the fob and 6 o'clock on the other, then rolled around a few times (envision pedaling a bike) would flare the copper back out to make a snug fit against the wood.
    – FreeMan
    May 2, 2022 at 16:16

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