Help: How to cut 16-24 inch pipe squarely

Hey, all, I have been doing some work involving 16-24 inch diameter pipe that needs to be squarely cut. I have been using some 10 inch
wide, 10 feet long aluminum flashing (rolled) as a pipe-wrap to mark the pipe squarely and then cut it which works okay but is cumbersome and not as accurate as I'd like. I'd like a solution that would enable me to cut the stuff quickly and accurately. I've envisioned some aparatus that would be made of a couple of pipes running parallel with a holder for the oxy-acetylene torch and a way to rotate the two pipes that would rotate the piece being cut but it's large and I only need something like this occasionally so a large piece of equipment isn't really what I want. I'd prefer a device that would carry a torch around the pipe or a device that would rotate the pipe underneath the torch, but something that would just mark the pipe easily and accurately would be an improvement over what I have now. Has anybody got plans, ideas, thoughts, or experience with such a device? I can cut anything up to 7" on my bandsaw, and I don't mind pipe-wrapping the small stuff like 8-10 inch diameter if I have to; it's the larger stuff that I use in longer lengths like the 16-24, sometimes 30 inch, that causes me fits.
Thank you in advance for your time and help.
--HC
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HC wrote:

Two roller conveyor sections , two rollers each - rollers not necessarily right next to each other . One section at each end of the pipe , and a mount of some type for the torch on one of them . I've been planning on grabbing a couple of extra rollers from work to make a roller cradle to cut the ends out of an empty freon bottle for my mini-forge . For my use , a couple of boards would work to hold the ends .
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Snag aka OSG #1
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Rent a pipe cutting outfit for torching and beveling pipe. On large pipe there is a chain affair that wraps around the pipe and a bug carrying the torch travels around cutting or beveling the pipe. Large pipe is not round so rotating the pipe is ok but you are constantly adjusting the torch as the pipe rotates. Randy

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Details on miniforge please.
Wes
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Wes wrote:

Google "Ron Reil" - he also has some stuff on abana's pages , or did at one time . Basically it's a 30 lb freon bottle with both ends cut out , and piece of (dammit , can't recall what it's called) material on standoff's , flat and fitted as a bottom plate . The rest of the walls are insulated with kaowool , coated with ITC100 or a similar product . There's a ton of links out there no nini forges . Here's one - ronreil.abana.org/minifor1.shtml
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I'll bet a piece of Formica or whaterver they call countertop laminate material these days, if wrapped around your pipe would make a nice square line. Same idea as your flashing, but it is wider and may resist bending "the hard way" better. Good luck, Andy
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They make devices to do just this. A clamp which fits around the pipe and a traveler (for want of a better word) that rides on the clamp and holds the cutting torch. I've seen them both hand cranked and motor driven. Very common in the pipeline business.
Bruce in Bangkok (brucepaigeatgmaildotcom)
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Try here (but don't look at the price tag).
http://www.hmpipe.com /
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The cheapo fixture is a piece of galvanized steel flashing (not aluminum) with 3/8" standoff blocks every few inches. Wrap around the pipe, clamp in place, use as a torch guide. To make it go easier, clamp a small guide to the torch head to keep your tip height constant.
HC wrote:

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Another suggestion for you. We mounted an old four jaw chuck on a small three phase gear motor and VFD to drive it. It can go from about one turn in 15 seconds to 1 turn in four minutes. Can clamp nearly anything. Use a die cart and angle iron to make a V block for long pieces
The turner is great for accurate torching, grinding, and welding.
Karl
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Thank you all for your suggestions and help. I'm going to try the countertop material (Formica or whatever they're using these days" first and until I can build a turning bed. We'll see how that works. I am going to try to get sections in the right length to wrap around the various sized pipes I use; that is, one length for a 16 inch pipe, another for a 24 inch pipe, et cetera.
Thank you all again.
--HC
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Keep Fomica (TM) or any of the other laminates away from the torch. They burn quite nicely.
HC wrote:

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As I recall, cast iron pipe installers use a Chain cutter. It wraps around the chain and there are cutters in the chain that score - like a copper pipe cutter. It would mark it nicely. Otherwise you need to think wide wheel and a set of them that are banded together in a hoop. as it rolls it won't skate sideways as it would be out of align and re-corrects.
But a long chain cutter might be the way!
For marking - you could use a sheet of heavy paper - or sheet metal that wraps around and match the side on the far side as it overlaps. The wide sheet can't align but one way. Scribe a line. Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com /
HC wrote:

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