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Cutting ss tube.

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  • Cutting ss tube.

    I have a job where I need to cut thin slithers of tube . The tube is od 25.4mm and is 1.5 mm thick. I tried a chop saw but it leaves a massive burr. My bandsaw does it but is slow and the blade doesnt like it. I have about 300 cuts to make .Any suggestions on cutting this tube ? The piece I am cutting needs to be 6mm .

  • #2
    Turn a piece of material to slip into the I.D. closely and long enough to keep the tube from collapsing if chucked in a lathe (a light interference fit). Then part the rings off with a very sharp and thin parting tool till the cutter just bites into the plug. Half way into the cut you can file the backside of the ring and scrape the I.D. on each successive cut before parting it off completely. Pull the parted piece off with a pliers and move to the next cut. You will still have to deburr the I.D. of the backside however when it comes off the inserted plug. If I were doing it I would grind my own parting tool from a blank the blade of which would be no more than ~ 2.5 MM in length and about 1.5 mm wide.
    Last edited by DATo; 12-03-2016, 05:09 AM.

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    • #3
      I notice when I face the tube it also leaves a massive burr. I am using an insert tool . I would suspect the hss would struggle with this but will give it a try.

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      • #4
        Not knowing how many parts you'll cut? When faced with similar issues for just a few parts I filled tube with hard wax, chucked it, turned fast with sharp cut off tool. Also drilled hole in the center to stick wood dowel rod in it to catch a rouge cut off from flying. You say the heat will melt the wax , you would be correct. This works for a few parts. You can also pour the wax in the cylinder, put in the freezer and get several more cuts. Frozen water works also, but that's the lathe! Tom

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        • #5
          The tube has no problem in terms of distorting .I dont believe i need an internal support.SS is just a bitch. I will buy a new insert for my parting tool and use coolant and see if there is a difference.

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          • #6
            Plunger,

            I don't think DATo's suggestion of using an internal plug was totally to stop distortion; if the plug is sacrificial, then it'll prevent burrs forming on the tube rings, as there's then no space for them to form.

            Bit like sandwiching material between 2 other sheets of material when drilling - the middle piece comes out with dead sharp edges but no burrs.

            Ian
            All of the gear, no idea...

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            • #7
              If you have carbide insert tooling that is not meant for SS, go with something like 70 m/min cutting speed. With HSS 7 m/min works very well on SS. In both cases use coolant.
              Amount of experience is in direct proportion to the value of broken equipment.

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              • #8
                Eugene,

                I cut a lot of s/s tubing 1.5 mm wall. I use the finest blade I have an 8-10 or 10-12 although this does not fit the 3 teeth rule with a slow hydraulic down feed I have so far gotten away with it. I pile the tubing in the vice in layers of even and odd numbers on top of each other with a clamp on top of the vice pushing down on the bundles. My length stop has a plate fitted to it that is square with the saw blade. I use an intermediary spacer for setting the length, which I remove once cutting is under way so that the pieces are free to drop into the chip pan.
                You might have some waste but it is surprising how quickly you will have your pieces cut.

                Werner

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                • #9
                  I used to buy hundreds of small short stainless tube for spacers. The company cut them using an electrolytic saw, a rotating copper wheel that was electrically charged. It essentially EDMed the tube and the ends were absolutely burr free. You could even specify a fairly large radius on the edges.

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                  • #10
                    Originally posted by Ian B View Post
                    Plunger,

                    I don't think DATo's suggestion of using an internal plug was totally to stop distortion; if the plug is sacrificial, then it'll prevent burrs forming on the tube rings, as there's then no space for them to form.

                    Bit like sandwiching material between 2 other sheets of material when drilling - the middle piece comes out with dead sharp edges but no burrs.

                    Ian
                    Thank you Ian. I should have explained it better. Also, people might wonder how one would scrape the front I.D. if there is a plug in the way. Obviously one would push the inserted support further toward the headstock and then deburr.

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                    • #11
                      I cut a lot of stainless steel tubing.

                      I have tried numerous methods. A bandsaw with proper blade does a pretty good job.

                      A traditional 'cold saw' is the best method, but these saws are expensive.

                      You can also use a chop style saw with a Tenryu blade (there are others as well) for stainless and a router speed control to slow the saw down if the saw has brushes. This is a poor man's alternative to the cold saw.

                      I've tried parting off in a lathe, it still requires deburring. The internal plug suggestion is one I haven't tried.

                      If all you have is a bandsaw, get the proper blade and deburr as required. It is the quickest method.
                      www.thecogwheel.net

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                      • #12
                        I had another bash at it this morning with a new parting tip. It was worse but I think the tip was designed for brass and alu. I went back to the old parting tip but cranked up the infeed and did it on powerfeed. It takes 5 seconds to part off .The advantage is I get a true face on one side but a massive bur on the other. It is so thick I battle to break it off with a pair of pliers. I am resorting to grinding it off on my knife grinder(homemade kmg) It doesnt take long to clean it up and is faster and more accurate than the bandsaw.
                        Werner I am battling to understand how you clamp it and do you not get deflection as it goes from one tube to another.?I think your machine is alot more rigid than mine. By the way I missed out on a v13 (shorter than mine but no bloody gap) for R21000 in Germiston .I would have loved to have another machine as tooling could be swopped over.

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                        • #13
                          How long do the pieces need to be? How accurate do the cut lengths need to be?

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                          • #14
                            How about a rotary tubing cutter like the type used for copper pipe? I don't know if the SS tubing would work harden and you'd probably lose a thou or few on the inside due the rolled edge but might work. You could still use the lathe as a power supply and set up a work stop so the cutter doesn't flip when the work is spinning.

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                            • #15
                              Originally posted by HWooldridge View Post
                              How about a rotary tubing cutter like the type used for copper pipe? I don't know if the SS tubing would work harden and you'd probably lose a thou or few on the inside due the rolled edge but might work. You could still use the lathe as a power supply and set up a work stop so the cutter doesn't flip when the work is spinning.
                              Actually you can cut s.s. pipe/tubing with a copper pipe cutter - I've done it, but you are correct, the resulting burr and roll-over would defeat the purpose. Your comment got me thinking though. Why couldn't the O.P. just cut the pieces off oversize after facing them and then just face the other side. I got so immersed in the original question that I ignored the obvious ... that's the way I would do it. If the parts are too thin I'd just make an aluminum mandrel (or even a quickie expansion collet) and face the opposite side in a secondary operation.

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