Cutting copper tube square

I am making a spirit burner from a slice of 54mm copper tube and I am struggling to get the ends square. Any tips I should know.

I have access to a Boxford lathe

many thanks

How long is the tube? Can you turn a bung from a piece of hard wood? Push the tube firmly onto the bung and go from there.Wood is messy to turn though, so mention it to the lathe's owner if that's not you.

If you chuck it very gently, a sharp tool will mark the copper if you turn the lathe by hand. Then hacksaw and file will finish the job. You could also turn a piece of steel or aluminium so that the tube pushes on and carefully use a parting tool.

A common method with cutting plastic pipes, e.g. underground waste pipes, is to wrap a piece of paper around the pipe so that the edge lines up where the paper overlaps. On your 54 mm copper the same method would probably work. Once positioned, hold the paper from moving and go over the edge all round with a Sharpie. Then remove the paper and cut at the edge of the Sharpie mark. I reckon the result would be accurate enough, assuming that you're going to fit an end disk with a soft or hard soldered joint.

If it had to be a lathe job, the fixed steady rest could help but I'd regard cutting thin copper tube with a parting tool as quite an adventure!!!!!!!! Filling the tube with a wooden bung (or maybe even Plaster of Paris) sounds like a good idea.

When you've done the job, please come back and show us a few photos of the result.

Best regards,

Swarf, Mostly!

Get a piece of 2 inch plastic waste pipe. Cut that & then, using some sand paper on a disc or the bench, get it as square as you can. when satisfied, cut a slit in it & snap it over the copper pipe. Possible with a bit of double sided tape to hold it in place. Cut along the edge of the pipe with a hacksaw.

On the other hand, I have a plumbers, eclipse pipe cutting wheel, that cuts 54mm OK & that cuts copper pipe nice & square. Can you borrow one?

Edited By Sam Longley 1 on 13/11/2020 16:42:14

A large V block or couple of angle plates could hold the tube square to a surface plate and then scribe a line all the way round, once marked out you should be able to carefully file to the line  which should be then be pretty square.

Mike

Edited By Mike Poole on 13/11/2020 17:37:26

This^^^

I have done with a belt sander clamped to my bench as well as the v block. To be honest it should be taken as a chance to learn file work. Once you have the feel it's a well learned notch on your belt.

Clamping very gently in lathe and going at it with a bench grinder by hand is perfectly acceptable also.

Woody.

Further to the excellent answers already given, once you have cut your slice of material from the tube place a sheet of abrasive paper on a flat surface. Using circular and figure-of-eight motions true up the ends of the part. Check your progress frequently with an engineer's square.

Thank you for all the great replies.

The idea of wrapping a piece of paper & then marking with a sharpie was a revelation to me and works well.

Tempted as I am to use the lathe I think that the suggestion to use this task a means of improving my filing skills is a good on so I'll try that.

Thanks again

Pete

May not be quite the same thing, but some time ago I was asked to provide a large number of 3/4" copper tube short lengths 1" long. No idea what they were for, I dont even ask !

I did it by mounting the tube in the chuck and supporting the overhang using a suitable plug held in the tailstock and parted off. The pieces remain on the support when cut and are easy to collect, no rooting in the swarf to find them.

I understand that this would not work in your case, not many lathes have a spindle bore that size, but might be of interest to others,

PS, The old "Paper around the tube " is an old trick, but it still works !

A quick online search for "pipe wrap around templates" will bring up the professional version of the paper round the pipe idea. As Larry pointed out it's an old trick but still in use. It follows the KISS principle.

Martin C

... On the other hand, I have a plumbers, eclipse pipe cutting wheel, that cuts 54mm OK & that cuts copper pipe nice & square. Can you borrow one?...

+1 ... the easiest solution. I have a smaller version that will do up to 22mm copper pipe bought from local M/Mart; usual disclaimer.

George.

Suitable size Jubilee clip,square it on pipe,tighten,hacksaw. Lynne

Lynne, I like that idea ! never thought of that one, so, learn something new every day.

This might be a little off topic, but I thought it might be worth a mention.

Many years ago, I saw a good trick for marking a pipe/tube at an angle, the tube in question being 8or 9 inches/

What he did was to spread a handful of soot on the surface of a barrel of water and having marked the pipe both sides, where it need to meet a flat plate, he lowered it into the water until both marks met the surface, then took it out.

The result was a clear black line, showing exactly where to cut. So simple !

Has Anyone ever adapted a tubing cutter to take a parting tool?

Hello again - although the tube was marked using the paper strip I found it very difficult to file square and in fact seemed to make it less square and shorter!

I resorted to using my lathe and turned up two hardwood mandrills with 2deg taper. Left one in 4 jaw & other in tailstock centre where slight pressure gave a good grip to the tube. (See photo)

Trimmed the tube at both edges with a freshly sharpened parting tool going right through into the wood.

Thanks again for such a wealth of helpful ideas.

Pete

I've a feeling this is a daft question or I've missed something but whats wrong with a normal pipe cutter to cut a square edge.

Martin P

I don't think there was a problem with a pipe cutter if you have one that will do that diameter. Most other suggestions were ways of doing it without spending money on a tool that will only be used once.

Martin C

thanks for that, I'm not a plumber but as someone who used pipe cutters as part of his job I just assumed we all had one.

Martin P