Not knowing where you are or what you are after this for means we can only generalise. If I was still at work I would get one of my pipe shop friends to cut a piece of 6"nb x sch 40 stainless pipe and cut and weld it into a machinable ring. We never had any outside diameter stainless pipe anywhere near 6", 2.3/4" was the limit I think and the wall thickness was probably14swg.

Another option would be to go to the local sheet metal company and get them to roll a ring of plate to suit followed by welding and machining to size.

A third option is to get a 1.1/2" class 300 (or 2" class 150) flange (preferably from a scrapped pipe) to use as a machinable blank.

The problem with all these options though is holding the part for machining without distorting it.

Martin C

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My find was 1/4” wall … so the Goldilocks Zone is somewhere between the two !!

MichaelG.

What's the problem with ring rolling? Most pipe is rolled and welded anyway. Could you roll and weld a ring out of oversize stock and machine the OD and OD to final size afterwards?

What is the application you want to use the ring for?

Edited By Hopper on 19/08/2020 05:05:33

One of the main reasons for adding at the very least your country in your profile ! Better if you are more specific, county, town but just country would be most helpful

John

Not sure it helps but a couple of near misses can be bought in the UK:

Stainless Steel Pipe 316 168.28mm od x 3.4mm (6" NB Sched 10)

Stainless Steel Pipe 316 168.28mm od x 7.11mm (6" NB Sched 40)

Bit pricey £68, and £114 plus postage for 250mm. No idea if the firm would ship to New Zealand and the postage could be scary! Anyone closer to home like Pipes NZ Ltd?

My local metal supplier sells offcuts but they ain't cheap. Even worse, they're mostly in the useless to me sizes favoured by his commercial customers. Not many machine shops near me, and the nearest emphatically does not allow the public to buy scrap. Nor do any local scrap merchants, these days they're all razor wire and angry dogs!

Dave

Or water jet cutting from flat plate or from a suitably sized pipe flange.

Might be worth looking around a ships chandlery supplier. They use all kinds of weird and wonderful stainless fittings such as port hole rings etc.

It's very nearly a washer

A curious response in my PM box from the OP re my suggestion of rolling a flat bar into a ring. I don't do PM discussions as it robs from the shared knowledge base of an open forum (and I wouldn't want to waste any more of Andre's valuable time with further suggestions) so leave it here.

From Andre ROUSSEAU

Subject: Ring rolling

I don't own a multi-million dollar CNC-controlled pipe rolling plant. Clearly you haven't attempted the task using typical home workshop equipment.

Edited By Hopper on 26/08/2020 07:05:07

You mention that ring rolling has been tried and found to be unacceptable, it may be that advice on the problems you have encountered would help produce an acceptable result. The roundness of pipe is not usually to machining tolerances so a skim at least will be required. A local fabricator may be able to make acceptable rings that could be a bit of a challenge in the home shop.

Mike

Hi Paul, you probably could do it by progressive bending on a press, if you can control each press depth to be the same and unless you used a clevis type pressing tool, you'll have to do it in two halves. 8mm thick may be a bit too much to hammer round on a piece pipe to get a good shape unless you can heat it to red heat. Rolling is always the best way to do it, and once it's welded and the weld flushed down, it can be returned to the rollers and a little over bend pressure applied to get a good circular ring.

Regards Nick.