Tool Advice: Cutting Aluminum

[PAR_WIG1350]

We have a small horizontal/vertical band saw from harbor freight as our primary cutting tool for aluminum, and pretty much anything else that can be clamped into it. It was a bit slow when we used it to cut through a 1" anodized aluminum shaft, but that was probably one of the toughest cuts it will ever have to make. We have had troubles with alignment in the past, most notably one indecent in which the blade became bent down the middle [like this--> ( ](not entirely sure how we managed that one) and it started cutting in rather pronounced curves instead of the fairly straight cuts it normally makes.

[Triple B]

I would agree with Cory, the noise is well worth the accuracy.
mike d

[Brandon Holley]

Most of this has been covered, but I just wanted to second the choice of a miter saw over a horizontal band saw.

A horizontal band saw will most certainly work for what you need, but it will be less accurate.

I personally enjoy the one and done cuts that a good miter saw/blade combo can produce.

-Brando

[sanddrag]

For years I've cut aluminum on a Dewalt 12" miter saw with a carbide tipped wood blade. It was very loud and and a little scary, but it made a clean cut every time. I could hold .005" on that saw. I will also say, I too have cut and flung small round stock on a miter saw. Don't do it.

At home I have a 14" vertical bandsaw that is made for wood, but cuts aluminum fine with a good blade. The Wilton 14" vertical bandsaw is designed for cutting metal. Of course, a vertical bandsaw is mostly for cutting plate, not long stock.

I've used horizontal bandsaws too and they're fine. Nice and quiet. However, it seems at some point the blade always wants to wander outward, creating a cut that is not straight.

If I were to go buy a saw today for cutting aluminum stock, I'd go buy the Evolution Fury 2 that Cory posted. If I had more money, I might get a more expensive dry cut saw.

I'm surprised no one has yet mentioned a Cold Saw. They work well and are very accurate, but are very expensive.

[Triple B]

Another saw that works well is a miter/porta band saw, works like a chop saw.
A benefit is that the blade runs in reverse rotation.
I will see if I can find the brand.
mike d

[DonRotolo]

Originally Posted by Dale

Our miter saw has a habit of grabbing things and flinging them around the room
<snip>
It's also crazy noisy.

It's been addressed already but here is a teachable moment for safety. Clamp the work securely using at least two clamps always. Anything less is just wrong.

For the noise, it's a good chance to promote hearing protection. We not only require hearing protection, but a brief warning to others in the room "chop saw".

We have both vertical and horizontal band saws, and a chop saw. Each has its place and value. For the vertical band saw, make certain the speed can be adjusted for cutting metal, and note that it can't cut every length like the other saws can.

[diviney]

We also have both a chop saw and a horizontal bandsaw. I completely agree that the horizontal bandsaw generally does not make precise square cuts.

In my opinion however, the chop saw is just plain dangerous particularly for students who do not always pay close attention to details. Absolutely - clamping the piece (no round pieces), but try as you may, clamping is not always as secure as it should be. Bullets of metal... plus, where do the broken carbide teeth wind up???

We use the horizontal bandsaw almost exclusively (and yes, sometimes some clean-up / filing is required). There are a few rare occasions where we call on the chop saw, but mostly our adults do those cuts (or VERY closely supervise).

I just feel even at best, the safety of a chop saw used for aluminum is marginal.

[Dale]

Thanks for all the great feedback. We do have a vertical bandsaw so the miter saw or horz bandsaw would be mainly for cutting long sticks of aluminum down to size.

If we go the miter route I was considering going to a 10" sliding miter saw like this. That would let us use less expensive 10" blades (rather than our current 12") and replace them more often. Also, my hope is that since you are cutting backwards, sliding the blade back towards the fence, it would be less likely to thrown the work around. Thoughts?

[sanddrag]

Originally Posted by Dale

Thanks for all the great feedback. We do have a vertical bandsaw so the miter saw or horz bandsaw would be mainly for cutting long sticks of aluminum down to size.

If we go the miter route I was considering going to a 10" sliding miter saw like this. That would let us use less expensive 10" blades (rather than our current 12") and replace them more often. Also, my hope is that since you are cutting backwards, sliding the blade back towards the fence, it would be less likely to thrown the work around. Thoughts?

Other than marginally cheaper blades, what do you really gain from the sliding saw for the purpose you intend to use it for? I'd rather have the rigidity of a fixed-pivot 12" saw. I'd think you'd be more prone to damaging the blade on a sliding saw, as it's more difficult to control feed pressure (2 axes). As for blade life, if treated properly, they'll last. On 696, our Dewalt 12" is running the same carbide tipped wood blade that came with it when it was purchased in 2002.

[Dale]

My thought on the 10" sliding miter was that it might be a tad quieter, the blades are cheaper, and it can cut an aluminum plate as wide as we're likely to use. Most importantly is my unconfirmed theory, which I'd love others opinion on, that they are less likely to grab pieces and fling them around. That's because the designer didn't have to trade off where the backstop was in relation to the center of the blade. The blade is always contacting the work from the side rather than the top.

I'm also intrigued about the option, inspired by Corey, of using Evolution blades on our 14" abrasive cutoff saw or even on this miter saw.

[sanddrag]

Originally Posted by Dale

I'm also intrigued about the option, i spired by Corey, of using Evolution blades on our 14" abrasive cutoff saw or even on this miter saw.

Do keep in mind that those saws are 2 or 3 times faster than the Evolution saw. There are these high speed metal cutting blades but I've heard reports that they don't last at all on steel. Not sure on aluminum.

[Tristan Lall]

My main preference in a mitre saw would be something that has versatility (e.g. rounds, flats and extruded sections) and a secure workpiece clamping system. I did not appreciate having to be careful to align the crown in the material with the imperfections on the table, so that the workpiece wouldn't shift during or after the cut. In fact, given a sufficiently good clamp, it would be easy to make the rule that nothing may be cut with the saw if it can't be clamped properly (i.e. you're not relying on hands to assist in securing the workpiece).

I've used both a Craftsman portable mitre saw and a benchtop Delta. Although they were both decent units, I wasn't really fully happy with them. The Craftsman was not designed with metal in mind: in particular the fence was horrible. This led to techniques that, in hindsight, were not particularly safe (even with extreme caution regarding the location of fingers, workpieces and clamps). The Delta had a passable fence, but the rotating carriage wasn't level with the rest of the table. This meant alignment was a chore—leave a gap and the workpiece settles during a cut. That was very annoying for precision work, and meant that angles were never quite right. You could cut length to within a few thousandths of an inch, but the perpendicularity was always wrong.

I have managed to fling parts with both saws; I'm not very proud of that fact. After having experienced this the first couple times, I started to pay a lot of attention to the blades—I found that the Freud metal-cutting blades (carbide tipped, with numerous small teeth with alternating left/centre/right profiles and narrow kerf) worked much better than a generic carbide blade intended for wood. This resulted in fewer screwups, but given the other faults of those saws, it was hard to achieve as rigid a setup as I would have liked. Consequently, cutoff pieces still managed to work their way loose and go flying, occasionally taking teeth off of the blade. (This gets expensive: those are $40 blades.)

Incidentally, those blades are not for steel, judging by what it says on the side of the blade: non-ferrous metal and plastics only. We used abrasive cutoff discs in the Delta saw for steel, and they worked fine. As an added bonus (in terms of peace of mind), abrasive wheels are a little more forgiving than 80 pieces of silicon carbide (which are just waiting for an opportunity to remove a finger).

Another surprising problem is blade deflection. If you've got a long piece of stock, and someone is holding the end, it's very easy to accidentally apply a side load to the blade as it's making the cut. Not only does this cause perpendicularity errors, it risks damaging the blade, and puts an unexpectedly large hole in the removable plug in the table.

Given all of that, I very much like the idea of a saw that doesn't require much human interaction, other than to push down. And find the right blade—the benefits outweigh any reasonable cost.

[Ivan Helmrich]

Personally, I like the horizontal bandsaw. Properly set up and maintained, they will cut square enough. Quieter and safer than the miter saw too. If you are set on using a miter saw, I can't agree more with the statements about clamping the work. The other thing to know is that the right blade makes a big difference in both safety and cut quality. Here is a link I found about hook angle. A blade with a high hook angle meant for soft wood, this is what you'll find cheap at the big box store, is much more likely to grab the work. More teeth usually means a smoother cut as well and increases cost. Buy a good blade once, don't abuse it and it will save you money in the long run.

Here's a link about hook angle:

https://woodtechtooling.com/FreudToo...dep12Hook.html

Ivan

[Brandon Holley]

Originally Posted by sanddrag

I'm surprised no one has yet mentioned a Cold Saw. They work well and are very accurate, but are very expensive.

This is the correct tool for the job we are mainly discussing (cutting aluminum extrusion). Not as intense or dangerous as a miter saw, and extremely accurate. The reason I didn't mention it was for the exact reason you stated, they are flippin' expensive!

-Brando

[Retired Starman]

A cold saw is certainly the correct tool to use, and I would suggest that any team doing much aluminum cutting get one regardless of the "high" cost.

I cut aluminum on my light duty 10" miter box saw for years with no trouble, the in the period of about a month blew up three $90 aluminum-cutting blades on my saw, usually with spectacular results in terms of throwing pieces of aluminum around the shop. By blow up, I mean that up to 1.4 of the carbide tipped teeth were stripped off the blade. These were high-quality blades with the correct hook angle for cutting aluminum.

I finally narrowed the cause down to worn bearings in the saw which allowed the blade to move around a bit, allowing the teeth to grab in the stock.

The last time it happened, the piece of flying aluminum angle hit my hand, fortunately doing no damage more than a couple of nicks, but I sat down and had a little talk with myself and decided if I was going to cut aluminum, I would rather spend my $1200 on a cold saw to do the job correctly than spend several thousand dollars in the emergency room getting my hand put back together. Every mentor needs to come to the same conclusion and recognize that they would rather spend the funds to properly equip the shop rather than having a student go through life missing part of a hand or an eye.

While a cold saw has capacity limitations, and most run on three-phase current, Grizzly and Jet make 9 and 10 in. saws that are reasonably priced for what you get, make very accurate cuts (I was introduced to cold saws in an industrial engraving shop where one was used to cut engraving blanks our of hardened steel with a precision of a few thousands of an inch parallel on all surfaces). They beat bandsaws for speed and accuracy any day of the year.

If you must use an electric miter-box saw to cut aluminum, get one with chop action, not one with chop and slide action. You just don't have enough control over the pulling action needed to carefully cut with a sliding saw. The blade rotation makes this a climbing cut, pulling the blade forward into and up on the aluminum. While this action is OK for wood, as with a radial-arm saw, it is dangerous to try to hold the blade back as you cut aluminum when the blade is trying to pull itself through the aluminum.

Dr. Bob
(45 years of machining experience and I still have all my eyes and fingers)