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plunger
12-03-2016, 03:33 AM
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 .

DATo
12-03-2016, 05:03 AM
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.

plunger
12-03-2016, 06:49 AM
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.

tincture500
12-03-2016, 08:37 AM
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

plunger
12-03-2016, 09:30 AM
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.

Ian B
12-03-2016, 01:23 PM
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

Jaakko Fagerlund
12-03-2016, 01:29 PM
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.

wern
12-03-2016, 01:48 PM
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

garyhlucas
12-03-2016, 05:46 PM
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.

DATo
12-03-2016, 06:40 PM
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.

enginuity
12-03-2016, 07:19 PM
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.

plunger
12-04-2016, 06:02 AM
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.

Smokedaddy
12-07-2016, 02:35 PM
How long do the pieces need to be? How accurate do the cut lengths need to be?

HWooldridge
12-07-2016, 04:13 PM
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.

DATo
12-08-2016, 05:42 AM
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.

metalmagpie
12-08-2016, 12:30 PM
Didn't see where you mentioned how long the pieces need to be. If they are short sort of like a wedding ring, maybe you would have
luck parting them off from the inside, leaving the burr on the outside where it's easier to get at with pliers. Or maybe a secondary tumbling operation?

metalmagpie

HWooldridge
12-08-2016, 01:53 PM
Didn't see where you mentioned how long the pieces need to be. If they are short sort of like a wedding ring, maybe you would have
luck parting them off from the inside, leaving the burr on the outside where it's easier to get at with pliers. Or maybe a secondary tumbling operation?

metalmagpie

He put 6mm at the end of the question but I'm not certain that was the length.

HWooldridge
12-08-2016, 01:55 PM
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.

Or ream out the resulting burr - might be able to chuck inside a 5C collet to minimize distortion on the thin wall.

Smokedaddy
12-08-2016, 11:08 PM
So you never answered my length question or I haven't seen it. I've cut "tens of thousands" (if not more more) of stainless steel electropolished pieces of tubing, usually 4" to 6" long in smaller tube sizes and 12" in larger bore. . On the smaller sizes 1/4" up to 1 1/2" I used Ridgid 29963 Model 35S tubing cutter which is specifically designed for SS and has a SS specific cutting wheel. I think the models are 35S and 65S and they have bearings in the hub, to decrease drag around the tube for a smoother cut. You will still have a slight burr on the inside but you can use a deburring tool or Swagelok makes a nice reamer. In the Pharmaceutica and Semiconducto world we use a facing tool since the end of the tubing must be perfectly square before it's Orbital welded. There are many 'brands' out there but we use something called 'Tri Tool'. I make a crummy video about 4 years ago showing some of the processes, one in the video at about 1:40 shows a Tri Tool in action.

https://www.youtube.com/watch?v=VFR518RDXlA

-SD:

I should mention I made a jig to hold a 20' (approximate) length of SS electropolished tubing, with stops every 4" or 6" along the length of the jig, with some plastic guides for the tubing. The tubing is spun with a drill motor. I just take the cutter, hold it up next to the guide and slightly and somewhat slowly turn the knob on the cutter. I can easily cut one every 10 seconds. Facing one end takes about the same amount of time. It's unacceptable to scratch the inter surface of the electropolished tubing, so you have to know what you're doing when you face. That wouldn't be a concern to you more than likely.

Smokedaddy
12-08-2016, 11:21 PM
Oops, here's the link to Tri Tool.

http://tritool.com/products/machining/tube-machining/tube-squaring/

-SD:

plunger
12-09-2016, 01:33 AM
I am cutting pieces 127mm long and then the smaller cut of 6mm is actually a handle I weld on the 127mm piece.I cut it open and I have made a mini bender and the small 6mm piece actually is a handle that I tig weld on the tube. It is an overflow tube for a hospital. The handle obviously cant have a bur on it as it will cut the operator. It is just very time consuming with such a big bur.

RichR
12-09-2016, 10:18 AM
Make yourself a parting tool that basically looks like this from above but with a shallower angle:

/|
/ |
/ |
This will minimize the burr on the piece that falls off.

smithdoor
12-09-2016, 11:15 AM
This simple if have lathe with a 1" [25.4mm] hole or larger

Dave


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 .

plunger
12-09-2016, 01:11 PM
Smokedaddy that is one hell of an impressive weld set up. I would hate to know what that costs.I have not tried a pipecutter but I a worried it would mar the tube where the rollers contact.
I can part it but as i have said the burr is huge but the cutoff time is 5 seconds. I tried an hss parting tool but it couldnt cope and dulled quickly to the point of actually making the workpiece glow red. I could pursue it with slower speed and different angles and flood coolant .

Glug
12-09-2016, 07:18 PM
I can part it but as i have said the burr is huge but the cutoff time is 5 seconds.

I went through the thread again and did not see this mentioned. They make parting inserts in three basic configs - neutral, left and right. It determines where the burr occurs. Which style did you try, where the burr was left on the part?

Have you tried a neutral? What if you used a left insert, that should leave the burr on the stock. You could then switch tool holders and face off that burr - either with a right parting insert or any other insert suitable for facing it off. Of course you'd want to avoid the interrupted cut, since you said the burr is substantial.

Smokedaddy
12-09-2016, 09:31 PM
... pipecutter but I a worried it would mar the tube where the rollers contact.


... BTW, it's not a pipecutter, it's a 'specific" tubing cutter for stainless steel tubing. The rollers, the bearing 'inside' the cutting wheel and the stainless steel cutting wheel are the trick. No manufacture makes a cutter like I've mentioned. I've been doing this for a LONG time, trust me. We are not allowed to scratch (even a hair line and is inspected with a maglite) inside the tube, NOR mar the tubing is allowed. QC would shut us down in a heart-beat. Naturally if you torqued the handled down like a gorilla you might put a faint ring on the tube from the wide rollers. This isn't your typical tube cutter used for copper tube. Even the expensive Swagelok doesn't compare.