How precision-cut Stainless steel tubes?

I would appreciate suggestions for cutting many hard stainless steel
tubes that are 3 mm and 6 mm diameter with a 0.25 mm wall and soft
(easy to bend with fingers) stainless tubes that are about 1.3 mm
diameter. Cuts are at right angles (I could conceivably need miter
cuts in the future). Cut ends need to be vertical/square. Some cut
lengths need to be accurate to 0.25 mm or 0.5 mm. I do not know the
types of stainless, because I bought the tubes as surplus. I’m in the
United States, so a power tool would need to be 110-115 volts.

Information I’ve found on the web refers to cutting larger-diameter
tubing.

I plan to use the tubes to make earrings (I make most of my jewelry
with industrial materials).

I’ve tried a jeweler’s saw (too slow, blades wear out quickly) and a
fiberglass-reinforced cut-off wheel on a hand-held Minicraft
Dremel-like device (fast, but impossible for me to control).

I’ve considered these hand tools: tubing cutters designed for
air-conditioning mechanics (for the 3 and 6 mm tubes), fine tooth
hacksaw blade, and carbide-grit hacksaw blade.

I’ve considered these power tools: Proxxon KGS 80 cut-off/chop/miter
saw with ferrous cut-off disk (close to $200); Proxxon KG 50
mitre/miter saw, which I can’t find in the United States;
Micro-mark.com’s miter/cut-off machine 15218 ($140);
harborfreight.com’s Chinese-made mini cut-off saw 42307-3VGA ($19.99

  • cost of disks, with concerns about quality at this low price). I
    like that the Proxxon KGS 80 has a guard that covers more of the
    disk/blade than the guard on the other 3 saws.

What you need for the blade is a High Speed Steel blade, which they
call “Jeweler’s Saws or blades” They are fine kerf, like a table saw
blade, but 1/2" to 3" diam. or so. Or you can also get carbide. What
power tool to use is different - I would use my milling
machine… I will say one thing, though, and take this
seriously: Do NOT use them on a flex shaft - they’ll take your finger
right off. They are made for the very purpose you have, though - all
you need is a machine, which you could almost make - an arbor with a
slotted table and a sliding miter holder… Try www.micromark.com for
ideas, maybe… The blades I mention are machinists - Enco, Msc,
Travers, or ebay.

I once drilled several holes in stainless steel and experienced most
of the anguish posted on google-able advice sites. It gets very hot
and glazes. I destroyed several high speed steel bits per hole. What
got me through all the rest of the holes was one cobalt bit and a
drastically reduced speed. Once it glazes, you can’t progress and
have to move to a fresh spot. There are cobalt hacksaw blades out
there and perhaps this route will give you the controlled slow rate
neccessary. Worth a try for under $10. Fill the tube with soft wire
and give it a go. Personally, I wouldn’t torture myself with anything
else.

The slitting or Jewelers slitting saw blades that John mentioned will
work but and it is a big but you will need a very rigid machine with
a very low speed to use them on stainless. The little machines you
have been looking at are not near rigid enough and probably are
running 30 times too fast for stainless.If they are run too fast the
blade will over heat and anneal and dull the blade almost
instantaneously. Carbide blades dont suffer from this problem but are
even more finicky about rigidity of the machine and quite costly (3"
dia X .012 thick blades are about $145 each) I use these style blades
in my horizontal mill on gold and silver and run the 3 inch diameter.
012" thick high speed steel ones at about 300 rpm. For stainless the
appropriate speed would be about 110 rpm. With the slightest lack of
rigidity or binding in the setup the saw will fracture throwing
pieces of itself across the shop so we always wear a face shield when
using them.

I think that if your budget limits you to the small machines you
mentioned you need to use an abrasive cut off type blade rather than
a toothed type saw blade. The cut will not be as clean but it will be
reasonably flat and perpendicular to the axis of the tube but if you
are going to be cutting a lot of these pieces then investing in a
machine to cut them with the slitting saw is probably less labor
intensive than the abrasive type saws. Or hire a machine shop to cut
them for you.

Jim

James Binnion
@James_Binnion
James Binnion Metal Arts

Jim (James Binnion) - referring to your greatly-appreciated advice,
what is the smallest/least-expensive machine you would suggest for
using a slitting saw to cut my hard stainless steel tubes (3 mm and 6
mm diameter with a 0.25 mm wall)?

Jim (James Binnion) - referring to your greatly-appreciated advice,
what is the smallest/least-expensive machine you would suggest for
using a slitting saw to cut my hard stainless steel tubes (3 mm and
6 mm diameter with a 0.25 mm wall)? 

To use a slitting saw on stainless tube I would still want a mill/
drill type tool where the tube can be rigidly clamped and the feed
accurately controlled. These can be had for around $1000 and there
will be some more expense in tooling. You can use the abrasive disk
type miter saws like the ones sold by Micro-Mark
(http://tinyurl.com/jqf2j), they are much cheaper but may leave more
bur and require more cleanup and be less accurate. Do not try to use
a slitting saw on the Micro-Mark tool it will not cut stainless at
that speed it will just dull the blade and may get way too exciting.
But at $119 (the current sale price) it is worth a try.

James Binnion
@James_Binnion
James Binnion Metal Arts

360-756-6550