Fixturing square tapered legs

Awl --

Starting material: 2" sq alum, about 8" long, symmetrically tapered to about a 1x1 sq, which my calc tells me is only about 3.6 deg (arctan 0.5/8).

Seems to me the easiest way to do this is to tilt the 4th axis on the fadal, and just face mill away. I can actually get the dimensions pretty well by just manually finagling the angle, until the cut is right.

I have to thread both ends of this leg anyway (1/4, 5/16), so I figgered I'd put a 5/16 set screw in one end, and attach a pc of 1" round, for a 5c collet.

I think I have the "handedness" of stuff such that it should tighten the material on the screw, god willing.

I'll mount the 4th axis and tailstock on a sub plate, and tilt the whole bidniss. I have ideas on how to do this, but if there are standard or particularly nifty ones, I'm all ears.

Altho I proly won't do this right away, eventually I'd like to make a 4th axis subplate with two hinged ends, such that you could make the letter "Z".

Then, with one hinge bolted down, and the other hinge end bolted to some riser block, any angle can be readily achieved.

But, if there is a quick'n'dirty way to do this in a vise, I'm all ears. The only way I can think of is to leave a lot of material on one end, for a good grip, and have 8" sticking out of the vise, and at the correct angle, with stops/risers within the vise to set the angle. But then subsequent ops won't be so easy on a trapezoid, holding-wise.

Reply to
Proctologically Violated©®
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Uh.... Why would you tilt the thing and face mill, when you could just mount it flat and square, and program the angles while side milling?

Leave maybe a half inch of extra material at one end. Mill a pocket at the end of a pair of soft vise jaws, to hold the square blank and also to serve as a length stop. Support the other end with a tailstock. Side mill two sides at the programmed angle. Unclamp and rotate 90 degrees. Then mill the other two sides.

Or, if you want to get fancy, mill a square into a collet for your indexer, or fit it with a small four jaw chuck, so you can do the whole thing without stopping to reclamp.


Reply to
Kirk Gordon

Use the side of an end mill minstead instead of a face mill and eliminate the need for tilting.

Reply to
Uhh Clem

Mindlock, of course! Hadn't thought of a tailstock with a vise!

Proly I'd do the angle 4th axis with some mini production, just for the speed/finish. But for now, your idea is practical.

Reply to
Proctologically Violated©®

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