Advice on cutting aluminum

Hi all,

I’m writing this as a humble coach who has just been injured for the first time in ten years with FIRST cutting aluminum on the miter saw.

It was, of course, due to a dumb decision and improper clamping on my part but it did make me want to ask what do teams do to accurately cut miters in shorter pieces of 1x1 or 2x1 aluminum?

My stitches thank you in advance of your replies.

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We never use a miter saw for aluminum because of that risk - only wood and pool noodles. Instead, our horizontal bandsaw can be adjusted for miters. There are no gradients marked on it, but it’s pretty easy to get around that with a $2 protractor. It takes a little longer to get set up (and then revert to the standard straight cut), but it’s much safer.

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…and the piece you are making, is the short piece…the rest of the stock (the long end) stays in the vise.

We generally use either a vertical band saw or a hack saw, but then we have relatively loose tolerances on most parts, because that’s all that’s needed for what we’re making. And we like to spend all our money going to more regionals, instead of on nice, useful equipment.

Cutting short pieces of any material can be dangerous.

Over the years I have made hundreds of cuts of aluminum stock with a miter saw. The correct blade does make a difference.

If miter cuts are needed always cut the miter on a long piece then do a straight cut to length.

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While I cannot give any advice for using the mitre saw I can say that.if I were in your position I’d start looking at buying a horizontal band saw. If you’re on a limited budget I would look around on Craigslist or Facebook marketplace for one and if you have a larger budget the sky is the limit.

We switched from a wood type Dewalt mitre saw to an Evolution metal saw with a sturdy clamp on it. We did have to give up some mitre cut capability but the increased safety of a slower RPM metal chop saw verses a mitre saw has been night and day.

image

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That looks like a nice saw. I’ve been using an abrasive chop saw, similar to that, at home for a long time…but it makes a mess, and only works on steel. At $100+ for a blade, I guess you learn to be careful with it, too. I expect the added safety makes it worth the cost.

While I’d still go for a band saw given ideal conditions if I needed something small and compact I would definitely go the direction of a slower speed chop saw.

Personally thought I think the increased cost and space taken up by a band saw is worth it for the safety factor alone. Even though that is a much safer option than a typical mitre saw with a metal blade on it you still have to have your hands somewhat close to a semi fast spinny blade and I personally like to keep my hands as far away from that as possible, even if in all reality it’s completely safe.

We managed to find an aluminum-capable blade for ours… and we don’t do miters on that.

Wood chop saw rpm is not suitable for cutting metal, even with a carbide tipped blade. After a couple of near misses, team 78 purchased this Makita cold saw: https://www.makitatools.com/products/details/LC1230. We also purchased a blade to fit the saw that is specifically meant to cut aluminum. With the much lower rpm, very sturdy clamp (can miter too), and the blade…all combines to clean square cuts and no accidents.

I’m awful sorry to hear you got hurt. I hope you heal soon and fully.

We got a cold saw for our school with a grant that has taken the place of the miter saw. We had used an Evolution brand with an aluminum cutting blade, but most of our precision miter cuts had been done on the bandsaw and cleaned up with a miter gauge and 12" disc sander.

If you mark it out and are careful you can do a decent job with one of these and vice. They also have a table you can mount it on to make it a vertical saw.
https://www.amazon.com/s?k=milwaukee+cordless+band+saw&adgrpid=59715638847&gclid=Cj0KCQjwi7DtBRCLARIsAGCJWBobn6n71cmEbY8hfA2I0fDnpNJwgtHe4PUy18axMd3nI8UGoWModlUaAl0DEALw_wcB&hvadid=274740044392&hvdev=m&hvlocphy=9020241&hvnetw=g&hvpos=1t2&hvqmt=e&hvrand=11673665585447781944&hvtargid=kwd-307394134239&hydadcr=20343_9690431&tag=hydsma-20&ref=pd_sl_8v3vy6j2od_e

Honestly the best tool purchase we’ve made…so far…has been a Roll-in Band Saw. Super safe. It is an investment, but cutting aluminum is such a common practice its totally worth every penny.

https://www.rollinsaw.com/ef1459?gclid=EAIaIQobChMI78TEt6Cs5QIViovICh1VgQ8IEAAYASAAEgL5mPD_BwE

Seconding the bandsaw. It’s a lot slower than a miter saw, but it does the job well and is pretty safe to use, given that you just need to switch it on and watch it work for you.

I’m curious exactly what happened to injure you. Our setup is a DeWalt 12" miter saw with an 80 tooth Freud Diablo blade. It works great in aluminum. For small pieces, make a zero clearance fence, and start from a longer piece.

We used a crappy crappy crappy delta 10" miter saw but I was able to dial it in for very accurate miters. If my part had a miter on one side only, I cut that miter on the end of a longer piece. Then I would set it back to 90 degrees and chop it to length. If my part had miters on both ends, I would do the same but keep it at 45 degrees instead of chopping it to length at 90. In both cases, I set up an auxiliary fence made of either MDF or decent plywood or relatively uniform thickness. This gives me a zero-clearance insert on both the bottom and back side of the cut. Another benefit of this auxiliary fence is that it can move the work in front of the very bottom of the blade, so all the cutting force is down, rather than back and slightly upwards (That may have been confusing, let me know if I need to explain better). The conference table manufacturing company that I work for also uses this technique when we cut aluminum on our panel saw. Another tip I taught myself over my 6 years of woodworking has to do with cutting things to measurement not available with tape measures. Say you need to cut a part to 25.9 inches. Instead of fiddling around with your tape trying to find .9 on a .03125" base scale :face_with_raised_eyebrow:, cut your part to a very accurate 25 15/16". Then with calipers, scribe a line .0375" from the end of your part. Then sneak up on that line. Basically you cut it long to then cut it slightly shorter. 25.9375 to 25.9. Hope this helps!

Sorry about your injury.

I guess I was lucky this year cutting a short piece of tube using a miter saw. I had a similar experience but escaped injury. I did notice one of the two C-clamps fly by my head. When I finally found it, I noticed it had slipped into the saw blade. Unfortunately (or fortunately) it damaged the base casting of the saw.

When considering a bandsaw, please ensure that it is meant for metal. The bandsaw we have is one for wood with a metal cutting blade. Many of the girls (all girls team) were terrified of using it and the miter saw.

A compact and inexpensive alternative to a full sized metal cutting bandsaw would be to use a portable bandsaw with an accessory table. Look through the descriptions for each of the tables to find which one fits the saw you have. Harbor Freight sells a portable bandsaw with decent reviews for $139. Wait until it comes on sale or there is a 20% off coupon. Such a setup is compact and light enouth that I have seen teams bring them to competitions.

Yeah,

I didn’t back a shorter piece enough and it blew back and caught my finger. The sound was horrible as was the blood. Fortunately, it only cut me pretty deep. 3 stitches on one finger and a gouge on the other. I’m a Coach who was mostly a figurehead for years, relying on other mentors. This is a new rookie team and we are still trying to get mentors so I’m a bit more hands on and learning the dangers myself.

I hope you have a speedy recovery. Also, hope to see you and your team here in Houston, say in April :slight_smile:

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Daniel,
I suggest you get a horizontal band saw rated for metal. After a couple of similar (but not bloody) mishaps over the years with chop saws, I bought a cheap one from Harbor Freight* (<$200 IIRC) for 3946. After a bit of TLC and dialing in, it made great cuts (clean, at the desired angle, sharp corners but no burs); you can probably afford a better one. If cutting a short piece, be sure to be cutting off of a longer piece that you can clamp really securely and the piece as well as you can, and run the blade slowly enough that the piece you’re making will not fly off even if it does catch the blade at the end (which it USUALLY won’t with a sharp blade). One thing to look at when selecting a band saw is to check on the price/availability of replacement blades; I discarded several options which sounded good except that no one seemed to stock the blades.

* The same one linked by @Jon_Stratis below. It was less than $200 with one of their “super coupons”. Also, I do not advise getting it delivered - the packaging is not up to delivery by FedEx or UPS; some of the TLC I had to do was to knock the motor shroud back into something approximating its design shape. The legs are also light, making the saw top-heavy; do not roll it across thresholds or other obstacles without enough hands on it to carry it if needed. Bolting this onto a workbench is probably best.

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