flaring large steel pipe on lathe

Anybody here has experience/recommendations on putting a large flare into the end of steel pipe using a lathe?

Pipe is 12" o.d., 1/4" wall (the piece is about 14" long). I'd like to put a pretty large flare into one end-- say about a 1" radius, and take it out to as much as perpendicular (90 deg).

Was thinking about setting up an oxy/acetylene torch w/ flame spreader positioned to heat the end of pipe as it turns, and mounting a roller bearing tool in the tool rest, to run against the inside end of the pipe and gradually flare it out to the desired profile.

Any thoughts on this?

Flaring 12" x 1/4" pipe would take an extream amount of heat and pressure to flare out to 90% and the outside of flare would be really thin, more than likly crack. Not sure what you need a flare for on that big but I would recomend welding a large enough ring to end of pipe and then turn it to shape in the lathe.
Tom

Also disagree with the OP's idea. That would take a gigantic lathe to withstand the forces involved. Nor would it be easy to simply roll it out into the desired shape. This is a specialized spinning operation using heat. Not to be casually undertaken.

I might suggest buying some pipe elbows of the proper diameter and splitting them with a plasma cutter or even a bandsaw if you can think of a way to jig it, and then weld your 4 pieces around the pipe end to achieve your flare. Sand the welds smooth and it would be about what you want. Such pieces can be purchased from Wagner, look at wagneronline.com for more details.

GWE

Thanks for the responses.

I do think that with the pipe sufficiently hot, the necessary force could be applied by the lathe tool. But applying/retaining enough heat without causing other problems (to the lathe etc.) would be the tough part, i guess.

What i need is the 3 foot long torch they used to cut off the pipe (leisurely, in about 30 sec) for me at the scrapyard. (He then returned to cutting semi truck engine blocks in half with it).

I'll look more into the idea of welding on pre-formed sections (thanks metalmagpie), although wagneronline.com didn't seem to take me to the right place.

Just a thought, If it hasn't GOT to be a one piece part, then I'd look in to getting a ring machined to the profile you want with a short weld neck type extension........ bit of effort welding and dressing you wouldn't know it's there.

I'm with the others on roll flaring in a lathe, I've never done it, but it sounds pretty damn scary to me if you don't know what you're doing.

Take care. Sami.

I have done this kind of thing hot, with a hammer and an anvil. Its slow, a couple thousand hits, but it works.

slow sounds like it might be a bit of an understatement. i've welded a bunch of these little flanges on so that floating flanges could be used, i wouldn't be surprised if you went to a shop that does exhaust work and they had them in stock. i don't know where in texas you are, but someplace that does exhaust work for the marine industry, or oil and gas work would have them.
are you married to the idea of spinning? from what i understand about spinning you need higher RPMs than most metal lathes can do, then again i've only seen videos of people spinning soft metals, like brass and silver, making small jewelry and decorative items.

Is this rolled flange going to be a structural component, or some type of art work or cosmetic use? If structural, I would sure advise welding it yourself or finding someone who can weld some kind of flange on that can then be machined to whatever type of flare desired. Rolling a flange will certainly thin the material rendering it much less ridgid, meaning not much structural integrity!

Dale Nelson

If done properly, you should not diminish the thickness of the metal. But it is a big job to do and to do right. Myself, I would probably take a smaller diameter pipe (2" would give you something close to what you want) and bend a hoop out of it. Then cut away everything that isn't a "flare" or "flange" and then weld it to the end of the larger pipe. Dress your welds and you have a nice flare on your pipe. The torch you want would be something with a rosebud type tip, not a cutting torch.
While writing this, I am thinking it might be easier to section your smaller pipe into quarters with a plasma torch or bandsaw first. Weld one end to your larger pipe and using lots of heat and the appropriate jigging and careful applications of hammer blows, start to wind your 1/4 section around the end of the larger pipe, tack welding it as you go.
Good luck.