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I have an abrasive cutoff saw that I use to cut metal, it runs at 3800RPM. You cannot cut aluminum with these saws, so I bought a carbide blade rated for 3800RPM.

I went to install it, but after looking in the manual I don't think it is such a good idea. It says "No toothed blades". A regular saw runs around 1200RPM.

Why can't I put toothed blades in my cutoff saw? The blade is rated for that speed, would there be a problem?

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  • $\begingroup$ I did call a company called cut technologies and they make a HSS blade that will work much higher than 3500RPM. They cost about 100$ than I want to spend, I might go that route. A lower speed cutoff saw is 200$ more than what I paid for my abrasive cutoff saw. $\endgroup$ Commented Feb 18, 2016 at 6:18
  • $\begingroup$ The 355mm metal cutting blade I found is rated for 1800 rpm, so you are vastly in excess of that. Having said that I've got thin makita abrasive discs that will neatly slice through anything I've tried, so long as the workpiece is rigidly clamped. $\endgroup$ Commented Dec 24, 2022 at 0:56

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I would certainly hesitate to install a toothed blade on a saw designed for abrasive disks. My biggest concern would be that the dynamic loading is likely to be significantly different and as these things are dangerous enough to begin with it seems and unnecessary risk that some unforeseen set of circumstances could cause a catastrophic problem.

If I were you I would get a basic cutoff or mitre saw designed for toothed blades. Multi-material saws are now readily available and woodworking saws work fine for aluminium and there aren't expensive.

There is also the consideration that it is not really good practice to use he same machine for cutting steel and aluminium as a mixture of steel and aluminium swarf is extremely flammable ie thermite especially when the steel cutting process is abrasive.

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Generally a company is not going to recommend you do something outside the scope of the intended product design because that would invoke liability. There are lots of variables like blade mounting tolerances, bearing loading, shroud design, chip removal, intended cutting material, motor hp and rpm as you mentioned. And because of these variables, someone like myself won't be able to tell you if it is safe or not.

That said, cutting aluminum with a high speed carbide blade is common industry practice. They are called cold saws in contrast to "hot" abrasive saws. They typically employ coolant and the cut speed is controlled by computer to ensure maximum safe cut speed.

For your situation, a regular wood circular saw or wood miter saw outfitted with a high-tooth-count carbide blade will cut aluminum profiles just great without any coolant.

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  • $\begingroup$ I do have a miter saw but I believe it also runs over 3000RPM. When I bought my carbide blade I got a high toothed count blade, I saw some that were lower and had a wide gap over 1/5" I can't imagine what would happen if the blade caught an edge. The problem is, my blade is 14", miter saw is 12". I'll have to return the blade. $\endgroup$ Commented Feb 18, 2016 at 6:15
  • $\begingroup$ Small tooth is a good bit of insurance so that you dont feed to fast and break a tooth. The tooth size doesn't matter just as long as you dont feed to fast. A higher tooth count will also last longer because there is just physically more cutting surfaces to wear out. It may have worked on your abrasive saw, but it would be better to just take the sure route and use a saw and blade that match. $\endgroup$
    – ericnutsch
    Commented Feb 18, 2016 at 7:31
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Imaging a strong hard blade snapping a chunk off on the 27th cut and bounces off the steel into your hand, arm, guy, teeth or eye. That will go right through eye protection and any leather. The point load at some portion of the blade was just we'll over 50,000psi to snap the steel and now it's all embedded in the chunk heading for you tendons and arteries. Us old guys can tell you stories of set ups like that killing and mutilating people for hours. The classic is when a buddy says look at this and starts pulling an x-ray out of a manilla envelope. We cringe and have to ask right away "Ring Shank?" 80percent of the time the answer is "Yep". The reason ER doctors had to start buying titanium pry bars and pliers is the improvement in construction steel. I was at a hospital Christmas party and walked up to the ER doc with a Guinness and said this is your beer. He looked at the two full beers I had and his almost empty one in his hand and said "this is my beer". "Nope this is your next beer because you glued face back together 2 months ago that glued my face back together. Everyone complemented his work since no on could see the scars. Then I had a life changing moment happen to me. The hospital was Denver Health that created the "level 1" triage system and the flight for life system for the world and is the best ER school in the world. 4 ER doctor relaxed anfer a few drinks smiled at me and one said what happened and when I said construction accident they all flinched and look away from me. A lot of groans and muttering "construction is the worse damage we see, and motorcycle accidents" turns out motorcycle get their head spun around and a massive amount of bone breaks. That's treatable if you survive. Construction accident a have no standard injury. It's just mutilated flesh of some random sort. The top ER doctors in the world wear uncomfortable with me after that and I could see the images flashing in their minds when I said anything so I excused myself. That pushed home just how dangerous it is and safety was easy after that. Been stitched up 3 times in the last year and had an ER trip from a pinhole inclusion on my foot. I knew it was bad and was on the phone giving the ER direction on treatments to prep as I drove toward the ER. I was getting prepped for surgery when a motorcycle accidents came in and bu.ped me. I was on IV antibiotics as soon as I got there and 4 hours after the accident I already had a fever over a 100 and rising. Literally a 1 millimeter round hole at the edge the steel toe in my boot. I wouldn't have a half my foot if I wasn't wearing steel toes. But I would want to trade places with the motorcycle rider that bumped me. (It was a commercial pressure washer, water 'disects tissue" and runs random through tissue. Pinhole in the top of my foot and it went forward and split 3 ways, around the side of my foot and between three toes, curved back toward my heel on the bottom of my foot spraying out farther back than it went in on the top. Over two months until I could walk and work.) Be safe. No amount of construction money can overcome a mutilated body when you want to hook up. But I still recommend doing practice prep with each partner explaining what to do when you say we have to go to the ER, NOW.

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  • $\begingroup$ I welcome you as a new and enthusiastic user to the site! I would try to focus in on narrowing down your answers to address the specific question. Anecdotes can be helpful, but maybe only after putting the direct answer up first. That way a reader doesn't have to go through the whole story to get the main idea. $\endgroup$
    – hazzey
    Commented Dec 23, 2022 at 14:08

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