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Frank Downey
07-18-2009, 12:11 PM
Do anyone have any info on oxy-fuel cutting machine something like the pantogrraph engraving machine that is in the machinist bedside reader that I could build and use to cut log chain gears out with?I could withstand being out a little on the tolarance some with it being log chain gears,but do you think that machine would withstand having a torch on it,or do you have another thought on a machine.I can't go out and buy a cnc machine now and need to cut these gears.I can draw out the size on paper and copy them on the machine was what I was thinking.

oldtiffie
07-18-2009, 12:37 PM
Frank.

I guess that the material you want to cut is pretty thick steel and is beyond a normal HSM shop plasma cutter.

So I'd suggest oxy-acetylene (aka "gas axe").

If you put a roller on the cylindrical part just behind the nozzles of the cutting nozzle you can use it like a roller guide on a wood-working router.

Make the pattern from say 1/8" steel plate and allow for roller diameter and kerf width. The pattern/guide can be cut quickly by hand and dressed with an angle grinder. Just scribe/set-out or mark-out a tooth etc. profile and another set of lines off-set for roller and kerf width as previous.

Set the pattern at the mid level of the roller on the cutting torch.

I'd have a trial run first - just to "get your hand and eye in" - and "just in case". The hardest part is keeping the flame at the right height and keeping the axis off the cutting nozzle vertical.

Dress it up with the grinder to suit.

Best of luck.

jdunmyer
07-18-2009, 09:13 PM
Frank,
They used to make what I would call a "pattern burner", a pantograph machine with an Ox/Ac torch head and a drive motor that followed the pattern. The motor had a magnet on the end of the shaft that would roll around the pattern while the torch did the burning. I saw a guy using one to make #120 roller chain sprocket "rims" that he'd weld onto the hub of a worn-out sprocket to make it like new. It worked very well, indeed.

Now I'll make you sick: I had one of these, but never used it. Gave it to a friend who also never used it and ended up scrapping the thing.

doctor demo
07-18-2009, 11:05 PM
A metal supplier/job shop that I used from time to time had a tracer cutter that was an oxy-acet torch that would cut anything that could be drawn on butcher paper with a sharpie.
At work We have an old panagraph machine that We took the torch out and replaced with a plazma torch head. It works prety well but You have to make sure the motor wheel does not come off the patern. Of course it only comes off after standing in front of it all morning without a glitch, then as soon as ya turn away for a blink it wanders off like Rainman is driving it.
I think that You could make one with out to much trouble, a small variable speed motor and some light tubing for the arms.

Steve

boslab
07-19-2009, 12:21 AM
have a look;
http://cr4.globalspec.com/blogentry/4344/DIY-Oxy-Acetylene-Profile-Cutter
they do work well, worth making yourself [ i use 1/8" plate pattern cut with an ASNM nozzle/mill/anglegrinder/knife and fork.
regards
mark

loose nut
07-19-2009, 10:47 AM
I use one at work all the time. It has a tracking head that follows a patten drawn on heavy paper with India ink, works well but newer designs are cnc. Not much good for the home shop, a new tracking head cost $4000.00 and the the table and drive will cost much more, even for a small one.

HSM magazine had a design for a pattern tracing pantograph style cutting machine many years ago if you can find it, looked decent enough for smaller jobs

8ntsane
07-19-2009, 11:12 AM
Hey Frank
I have one of the old Victor brand patteren cutters. It is the type that has the magnet on the motor, and that follows a pattern that has been cut from sheet metal. The control box has a vari-speed dial and when you get the hang of it, they work quite well.I have been useing mine since around 1984 when I bought it new. I do admit that it frustrated the hell out of me at first, as getting the speeds set up properly was a pain, and the cutting tip size had to be right as well. My old Victor pattern cutter has made thousands of very hi-quality brackets for me over the yrs, but they do take a while to learn how to use one. I havnt used mine in a few yrs now, but I wouldnt ever part with the thing, I maybe old, low tech compared to todays Plazma cutter rigs, but it sure does a nice job, after you learn how to run it. I used mine to make chassis brackets out of 3/16 and 1/4 steele plate mostly, and on ocassion, it was cutting 1/2 plate, and worked just as well.

Paul

Frank Downey
07-19-2009, 03:38 PM
man that is a great site.Thanks for all of the info