Cutting 6" Alum. Channel

[lynnl]

An urgent (as in DOD contract) need has arisen to make several hundred assemblies of 6" aluminum channel, which will entail lots of bevel cuts crosswise. Bandsawing won't work. This channel is 5/16 thk accross the bottom, with 2" walls that taper from about 5/8 to 3/16 (radiused inside corners).
Would this be doable on either a tablesaw, or radial arm saw (by feeding the radial saw carriage back into the cut to avoid climbing)? (Wearing out the equipt. is not an issue here.)
Or does anyone have any other suggestions?

[Forrest Addy]

I suggest a radial arm saw (RAS) with an ATB non ferrous blade. Use a commercial grade RAS with a powerful motor.

Radial arm saws are flexible. Cook up a way to strongly a safety pointbrace the overarm to the saw's base. This will prevent the cut from drifting out of square as well as a safety point.

Set up the saw in a plywood booth and have a 2 HP DC sucking up chips right at the point of operation. Organize the job. Feed the material in along horses with rollers at RAS height. Make a set of good strong flip stops.

Equip the operator with ear protection and a face shield. An over-the-head air fed hood respirator is also a good idea.

By all means push the saw into the work. A runaway climb cutting aluminum on a RAS may destroy the saw's yoke so ensure the saw will be used in the "conventional cut mode'. Set up a screen door spring to ensure the saw's natural position is at the operator's end.

Make a simple hold down you can step on that holds the piece and the drop.

A 20 ft length of 6" alum channel still weighs about 90 lb. Give the operator a helper. The job will go over twice as fast and be much safer.

[ShavingMaker]

Have you thought about having the company that does the extrusions cut them to the right length? They do provide that service. Might be quicker and cheaper, maybe not.

[Paul Gauthier]

I would not use a RAS for this. RAS's cut by climbing and frequently grab and pull themselves through a cut until they get jammed or someones fingers and hand are on opposite sides of the blade. Not saying that everyone who uses a RAS is so clumsy I am sure that is not the case, I have one myself and use it almost daily. There is one RAS I might try it with. It is from Sears and has a device that prevents the saw from being pulled thru the cut too fast, there is a cable attached between the columm and the saw carriage it will only move as fast as one of the three setings will allow. I have found this to be a great improvement over my older RAS. Also if using a RAS for this I would reccomend a face shield, gloves and double hearing protection as this cut will make a lot of noise.

One more thing, one can get a horisontal band saw from MSC for a coulpe hundred bucks, would this be a better alternitive????????

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Paul G.

[lynnl]

This shop has a large Grizzly Horiz. bandsaw (at least 7 X 12, or bigger) and also a 14" cold saw. Per my son-in-law, whose problem this is, neither of those can handle the bevel angles. Obtaining proper lengths from supplier isn't the problm...it's all the many different angles required, on different length pieces. And the real issue here is speed. They've already shipped one prototype, which they had time to cut and assemble leisurely, but now they have to start moving 'em out the door at a hot pace. This is one of those "can't wait" jobs.

[Stepside]

If the money is there buy a "Roll-In" Saw and the right blade and band saw the parts. I can hold a 1/32 or better with good fixtures. Paid $3200.00 for the saw new and paid for it with two jobs. A big Marvel would be even better.

[Alistair Hosie]

Lynnl
would a sliding mitre saw do as it does not rely on a climb cut this could be fitted with a proper blade also I have a metal cutting chopsaw with a large aluminum cutting blade fourteen inches with 140 teeth specially designed for aluminum .But the sliding mitre pushes the sawblade from the front of the work through the job to the back so should work here is mine. Alistair
Mitre Saws
Scheppach Capas 3 Pullover Mitre Saw. Said to be the biggest portable
Mitre saw ever. It weighs 26kg, and the blade diameter is 305mm. ...
www.poolewood.co.uk/Saws/mitre.htm - 54k - 16 Jan 2003 - Cached - Similar pages

[Spin Doctor]

I'll go with stepside. Buy the Marvel do the job sell the saw One of the easier saws to do bevel cuts on

[crypto]

If the contract is fat enough to permit the purchase of a machine tool then why not purchase a good COLD SAW. These machines are made expressly for such projects and jobs.

They are compact, their small footprint takes up very little shop space.

[ytsudwas]

I have used a standard chopsaw for this type work. Use a good carbide tipped blade with ATB. Secure the workpiece with a jig.