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View Full Version : Cutting Aluminum Sheet (1/8" through 1/4")



Sandy H
11-06-2005, 11:19 AM
One of my hobbies involves me making some heavy duty enclosures, with appearance being priority over function most often. I have made a few, but either end up with a pretty poor fit from shearing the panels or end up spending way too much time squaring the sheet on the Bridgeport.

I know many people use table saws for cutting non-ferrous plates, but my table saw is a belt driven Rockwell 7 1/4" from the mid 50's. I'm just a bit chicken to try that and don't think I would really get a good result due to the blade slipping.

At work, we use a cold saw to cut hydraulic tubing all the time. I love that machine because it is quiet, small, non-violent and does a great job. I'm wondering if it is a realistic goal to make a similar contraption for cutting these aluminum plates.

My plan would be to use a gearmotor of some sort (salvage or possibly using a vari-drive unit I have) to spin a cold saw type blade somewhat slowly and make a self feeding table to cut the plates. I'm sure this is possible, but I am pondering the practicality for doing this in a mildly equipped home shop. I was thinking maybe a 24-30" stroke for the table, using plain threaded rod run off the gearmotor or a second motor for the 'powerfeed'. All cuts would just be for making square panels (previously sheared to +1" or so) at a max size of 20"x20". No angled cuts would be needed.

If anyone has suggestions or criticism for the idea, I'd like feedback. I have a mill, lathe, buzz box, china bandsaw and a boatload of woodworking tools. I am somewhat competent with all of the above items as well!

Thanks for any suggestions or comments!

Sandy.

DR
11-06-2005, 11:41 AM
Aluminum cuts well at cutter speeds similar to wood cutting machine speeds. So you don't need to slow the blade.

If finances permit, buying a nice 10" table saw for aluminum cutting may be a better idea than a custom machine. Aircraft manufacturers cut aluminum on table saws all the time. Adapt some sort of mist system to lubricate the blade. You do need a rigid holding system, kick backs on aluminum plate are a bit worse than on wood!!

ERBenoit
11-06-2005, 06:43 PM
I rough cut all my aluminum work with a Delta 10" (3HP, 3450 RPM) table saw. A lot will depend upon the capacity of the saw and using the correct blade. I have cut up to 3/4" without any problem, though I am mostly cutting maximum of 1/2". I use it for roughing mostly, though I will cut finish long pieces of 80/20 extrusion on it with excellent results. Granted, not a milled finish, but not that bad either. I use a 80 tooth TCG carbide blade and Cut-Ease as a lubricant. Lubricant is applied after every cut, thus ensuring a clean cutting action due to the reduction of chip welding and steady lubricating. I have found less than ideal results ("smeared" cuts) if as above was not done. Be safe, use a splitter with anti-kickback pawls and a full face shield if the saw does not have a blade guard. The anti-kickback pawls may not prevent a piece from being kicked right out of the saw, (can't dig in as if it were wood), but may slow/hold it down. Feed the stock only as fast as the saw will take it, over feeding will cause trouble. The saw will throw the chips everywhere, and they are hot. The saw I use has fired back at myself twice, luckily it was "only" polycarbonate, and I was only hit once. Hurt like Hell, did puncture a demin shop apron though.

Suppliers may offer cutting services. The supplier I buy from does, and can offer tolerances of .005". You could check into that also, may take out a lot of work on your end.

[This message has been edited by ERBenoit (edited 11-06-2005).]

barts
11-08-2005, 12:24 AM
I just use my model 77 circular saw to get it close to size;
a quick pass on the Bridgeport running really fast doesn't
take long if I need to get really close to size.

- Bart

Charles Lessig
11-08-2005, 07:16 AM
A half inch variable speed wood router with
a two flute 5/8 inch carbide cutter and band
saw wax as lubricant works quite well on
aluminum plate up to about 1/2 inch. Use a
straight edge which can be a sheared strip
and clamp everything down well. Mark where
the straight edge was at the end of each
pass before you unclamp it as you work
toward the final size. Don't take off more
than a 16th at a time. Wear goggles, ear
muffs, and get ready for an aluminum snow
storm. Charlie

Wirecutter
11-08-2005, 11:03 AM
Interestingly enough, I've had exactly the same problem of late. I had to cut several 1/4" plates of 6061. I purchased them cut, but I knew they'd be using a table saw to do it, so I had to order over-sized and expect to trim them myself. Well, the only thing I have that will do a good job of it is the Bridgeport. Edge-trimming 10"x19" plate is a little interesting, and nearly as large as can be handled on the machine.

I wound up clamping 3 plates flat on the table. Cuts in the X direction could simply hang off the edge of the table - no problem. But I didn't want to attempt to do the same thing with the Y cuts - I wanted to avoid unneeded setup steps. I also didn't want to mill into the table.

I have already trammed up the mill, and I know it's within .001". I load the collet with a suitable end mill, and lower it to the table with the spindle motor off. I put a piece of paper between the mill and the table, then adjust the quill stop so the paper barely drags on the mill, and doesn't tear.

http://mysite.verizon.net/vze8no8e/sitebuildercontent/sitebuilderpictures/setup1.jpg

When I'm done, the edge of the plate is faced off to a thousandth or so, and looks like this:

http://mysite.verizon.net/vze8no8e/sitebuildercontent/sitebuilderpictures/done.jpg

There is a very thin edge that's not milled, and the table is unscathed. This can be bent over and broken off by hand. After a few light passes with a file, it looks fine, and is easily "in spec".

It sounded like a hokey idea when I was setting it up, but I was impressed with the final results. All four edges were milled on one setup, so they're also dead-on square.

Is this suitable for a tips book?

-M