--I'm thinking of buying one of those things that uses a hand drill and a hole saw to make curve cuts in tubing, for welding, etc. My one and only experience using a hole saw to cut saddles in a pipe were pretty disappointing; i.e. the hole saw wanted to wander off-course even tho I was holding it in a collet, on the mill. Maybe just a lame collet, or is it the nature of the beasts? Anyway, to anyone who's had to do this sort of thing tips appreciated.
You might want to start here:
Ed,
I have a "joint jigger that I used for cutting 4130 steel tube for a airplane engine mount. Biggest problem was getting good hole saws, cheap ones just ripped the teeth off.
Found it was easier on the tougher angles to "fishmouth" the tubes on a grinder.
Just my 2 cents.
Look at my Subaru Engine conversion link below to see the tubing work my brother and I did.
Bart
The only real problem with them, is that nobody makes fine tooth bi-metal holesaws.
The regualr coarse tooth ones are brutal on thin wall tube. I just use my lathe for this. You make a tube clamp for the toolpost rest of your lathe and clamp the holesaw in the chuck.
It allows you very careful feed of the tube into the holesaw.
Joint jiggers work best for aluminum tube of heavy walled steel.
Another way to go is a hogger end-milling cutter in a bridgeport and a tube clamp for your mill table.
I used a joint jigger in combination with a grinder. Yes the small bi-metal hole saws are very coarse and can tear apart the end of a tube. So go slow. Also the angles one can cut are somewhat limited. If you want angles less than 45 you will have to modify the way the tubing is clamped into the jigger. I have to be honest, some practice with a silver pencil and a pair of tin snips and I was able to make fishmouths with real good fits for welding faster than setting up the joint jigger. Consider in some clusters you will have 5 tubes coming together. Some nipping with the snips is the only way to go. My 2 cents worth.
Ebby Hatz Classic s/n 37
--Thanks, gang, for all the advice. Decided to get the HF cheapie; I'm doing a pile of 1-1/2" tubing and it would have made a ton of dust to grind them all the way down. I figure this contraption will at least minimize the grinding aspect of the problem. --Still and all, if I had my druthers I would have gotten the arbor-press or hydraulic press variation, but I haven't seen one of those for less than a bundle... --In other news there's a really great book called "Performance Welding" that, amongst much other good info has a primer on how to use the hole saw version.
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