Miter saw as chop saw

[ckucia]

Recently bought a Dewalt sliding miter saw. Very nice machine although expensive.

So I have my old Craftsman 10" 5000rpm basic miter saw. Have had it for probably 20+ years.

Wanted to find something to do with it since it's not worth much on Facebook Marketplace. Could really use something for cutting metal as even a portable bandsaw is out of budget right now and a hacksaw gets old fast. Angle grinder is always an option, but I realized of all my tools, that one has injured me the most, although thankfully never seriously.

So like many, I started researching whether I could use some sort of cutoff blade on the old miter saw.

I know this has been kinda beat to death, but... One of the arguments I see against this is that "wood saws run too fast" or "metal chop saws run slower". But looking at chop saws, they're running around 3800-4000 RPM with 14" blades. I see 10" metal cutoff blades with a max RPM rating of 6000+ rpm. When you do the math, the circumference of a 14" blade is about 44" and a 10" is about 32". 44" @ 3800rpm is 167,200 inches per minute at the edge of the blade. 32" @ 5000rpm is 160,000 inches per minute at the edge of the blade. That seems like a pretty negligible difference to me and the wood miter saw with the metal cutoff wheel is actually the one running slower.

There are other valid arguments against doing this - the motor not being sealed and exposed to metal dust, the blade guard being plastic (although the upper half on mine is metal), inability to solidly clamp unless modified. But I don't see the speed as being a problem.

On the plus side, using a wood miter saw with a metal cutoff blade seems safer (by virtue of being more controlled and less exposed) than using a typical angle grinder by hand with a large cutoff wheel. A 9" angle grinder runs at 6500 rpm (that edge is moving at 183,690 inches per minute) and half the edge of the blade is exposed along with one entire face and half the other, right next to your hands. If I were to put a 10" metal cutting blade in my miter saw, (removing the plastic guard and leaving the half-metal guard) half the blade would be exposed but only half of both faces and my hands would be further away. Of course, the edge of the blade would always be pointing straight at me inside the guard on the miter saw which is not always (but not never) the case with a large angle grinder.

I'm undecided if this is worth trying as a general reluctance to use something dangerous for other than it's intended purpose, but I'm not seeing the speed or safety issues as long as I were to fab up a solid clamping system. I think the dedicated chop saw is slightly safer, but I think the wood miter saw with an appropriate cutoff wheel is safer than using a large angle grinder. Safest of all would be just to pull out the hack saw.

Is there something else I'm missing?

 

[sparky 1971]

It's a little different, but I bought A 7-1/4" miter saw for the sole purpose of using it to cut metal. I haven't had any problems with a 7-1/4 blade listed for ferrous metal yet. I recently replaced my 10" Ryobi slider and considered a metal blade for it, but haven't gotten any farther. Since I also have a regular chop saw, I may never do anything with the Ryobi. Then again, I'll be following this thread and I may decide to do it.

 

[tyyost]

The only issue I see is that you really need a way to clamp stock in a metal saw. It is a much more violent reaction when a piece of tube or angle slips with a ferrous blade vs a 2x4.

The old taboo was abrasive blades, they were nasty, would melt plastic guards, throat plates and anything else in short order. The grit didn’t mix with the machined surfaces of wood saws, Consider an appropriate ferrous blade that is rated for your saw, clamp the work, and go to town. I’d probably replace the throat plate with a piece of wood and make it zero clearance for the blade to keep swarf out of the miter mechanism but otherwise saw on.

 

[tarbellb]

Spinning a carbide tipped blade at those speeds gets real tricky real fast.

Most likely is that your piece wont be sufficiently clamped and will move.
Big movement = shrapnel
Small movements= carbide teeth break off your $$ blade

Youll get a few cuts, but really its not ideal unless you get a really great clamping method.


Maybe dedicate the saw to miter cuts only, set at 45* and never move it

 

[engineer2]

I've cut aluminum on my 10" miter saw. You have to go slow and steady. Your carbide blade will dull quickly.

You may consider one of those plug-in speed controls sold at HF or any big-box store.

Harbor Freight Tools – Quality Tools at Discount Prices Since 1977

Harbor Freight buys their top quality tools from the same factories that supply our competitors. We cut out the middleman and pass the savings to you!

www.harborfreight.com

 

[kelpaso1]

Why ruin a 800-1000 dollar saw cutting something it was not designed for? A metal chop saw is a couple hundred.

 

[tyyost]

After reading this I went blade shopping - a 10” ferrous blades max speed is around 3000 rpm for the Diablo and DeWalt is 1800 rpm. That said, the speed controller above should resolve your speed issues. Finding a 3000 rpm blade with a 5/8 arbor seems tricky.

I guess the question ends up being is a $20 speed controller and a $50 blade and some clamps put you ahead of a dedicated machine, be it a portaband, chop saw, or other tool. Keep us posted on your decision.

 

[tarbellb]

After reading this I went blade shopping - a 10” ferrous blades max speed is around 3000 rpm for the Diablo and DeWalt is 1800 rpm. That said, the speed controller above should resolve your speed issues. Finding a 3000 rpm blade with a 5/8 arbor seems tricky.

I guess the question ends up being is a $20 speed controller and a $50 blade and some clamps put you ahead of a dedicated machine, be it a portaband, chop saw, or other tool. Keep us posted on your decision.

You will lose torque with that speed controller, possibly making it inadequate for cutting purposes.

Cutting aluminum with a carbide blade at those speeds is not a issue. Lots of shops run a setup like this.

A different story when it comes to steel, SS, etc...

 

[tyyost]

Cutting aluminum with a carbide blade at those speeds is not a issue. Lots of shops run a setup like this.

I wasn’t thinking the op was cutting aluminum, and since he hasn’t been back I’m guessing he meant a 10” abrasive blade, as they seem to be the only ones rated to 6000 rpm.

If that’s the case I say if it’s a throwaway saw at this point he has nothing to loose. I doubt the longevity of the saw with abrasive blades, but it’s better than a hacksaw or the $20 he’d get selling it if he has a use for it.

 

[MushCreek]

I use an abrasive blade in my beat old 10" Ryobi. It's loud and messy, and the blades don't last very long. I bought a big old horizontal bandsaw, so I stopped abusing the miter saw.

 

[seber]

Look at a dedicated chop saw. Notice that one end of the piece to be cut hangs out in the breeze. There is a good reason for that. Metal is not as forgiving as wood. If the cut end flexes back even a little bit, the blade explodes. I've seen it happen with a radial arm saw. You already removed the lower blade guard and will have poor clamping no matter what you come up with. What you propose is a gamble with suicide.

 

[jives]

I put a Diablo Steel Demon Cermat II blade in a circular saw -- as recommended by the manufacturer -- and it works great. The blade is built for 5800 RPM for a 7 1/4" blade. Diablo does make larger metal cutting blades for slow speed cut off saws, but can a 7 1/4 blade be easily put in a chop saw? Clamping is important. There is not much forgiveness if the stock begins to chatter or bind. BTW, is use my old corded Skilsaw for the metal cutting, leaving the cordless Makita for wood.

 

[ckucia]

Sorry I missed some replies - stopped getting notices because I checked from another device without being logged in to trigger the notices again.

I haven't made a decision yet, but I'm leaning away from both this or a chop saw. I realized I'm starting to really hate loud tools. The miter saw and table saw cutting wood are about as much as I really want to deal with these days. Maybe starting to get old, but we also live in a remote, rural area and I've gotten used to the quiet - it makes loud tools seem a lot louder than when we lived in the city under the flight path to a metro airport.

Much as I like the speed of some sort of chop saw, really what I need is a bandsaw of some sort. I might use the old miter saw to cut aluminum, but if I'm going to cut anything ferrous, I guess I'll have to get some exercise with a hacksaw or save my pennies for a bandsaw.

 

[gungatim]

I've cut aluminum on my 10" miter saw. You have to go slow and steady. Your carbide blade will dull quickly.

You may consider one of those plug-in speed controls sold at HF or any big-box store.

Harbor Freight Tools – Quality Tools at Discount Prices Since 1977

Harbor Freight buys their top quality tools from the same factories that supply our competitors. We cut out the middleman and pass the savings to you!

www.harborfreight.com

LGR

 

[Forgottonia]

I bought the cheapest mitre saw I could find ($40 or so), put a diamond blade on it, and now use it as a chop saw for ceramic tile. I have a nice tile wet saw for making long straight cuts. But the little chop saw works better for shaping tile to go into odd shaped places--like around drains, curved corners, etc.

 

[Al Borland]

I've used an old cheap one for cutting pipe and rebar type stuff for years.
Only real issue has been metal filings getting in the motor.

 

[ycgoat]

I have a chop saw I used once upon a time with an abrasive saw blade and my problem was the sparks melted the plastic around it. I just tried a metal cutting blade and first the 1-1/2 angle moved around so I clamped it, then on the 2cnd cut it got hot and melted the plastic on the base.

Has me questioning the metal cutting blades at the higher speeds. the ratings are probably safety ratings not effectiveness. Or as mentioned above I may have destroyed my blade when the metal walked on the first cut.

 

[huzaen]

I wasn’t thinking the op was cutting aluminum, and since he hasn’t been back I’m guessing he meant a 10” abrasive blade, as they seem to be the only ones rated to 6000 rpm.

If that’s the case I say if it’s a throwaway saw at this point he has nothing to loose. I doubt the longevity of the saw with abrasive blades, but it’s better than a hacksaw or the $20 he’d get selling it if he has a use for it.

How long have you been using this product?

 

[ckucia]

Thanks for everyone's comments.

Been thinking about this and I believe I can take the motor, blade and guard off the chop saw and mount a basic angle grinder to it.

That pretty much gives me the best of both - rigid one-handed operation of the angle grinder at any angle with a motor and speed appropriate with the blades and materials.

 

[tarbellb]

Thanks for everyone's comments.

Been thinking about this and I believe I can take the motor, blade and guard off the chop saw and mount a basic angle grinder to it.

That pretty much gives me the best of both - rigid one-handed operation of the angle grinder at any angle with a motor and speed appropriate with the blades and materials.

That sounds interesting, definitely post pics and updates on usage

 

[kelpaso1]

Thanks for everyone's comments.

Been thinking about this and I believe I can take the motor, blade and guard off the chop saw and mount a basic angle grinder to it.

That pretty much gives me the best of both - rigid one-handed operation of the angle grinder at any angle with a motor and speed appropriate with the blades and materials.

What a waste of time.

 

[rancherbill]

That pretty much gives me the best of both - rigid one-handed operation of the angle grinder at any angle with a motor and speed appropriate with the blades and materials.

Pics please.

It seems you are buggering up 2 good resalable units to make something like this. You should sell one and just turn the angle grinder into this.

https://www.google.com/search?q=mak...MBFsQ_AUoA3oECAEQBQ&biw=1016&bih=463&dpr=1.89

 

[vwpieces]

Thanks for everyone's comments.

Been thinking about this and I believe I can take the motor, blade and guard off the chop saw and mount a basic angle grinder to it.

That pretty much gives me the best of both - rigid one-handed operation of the angle grinder at any angle with a motor and speed appropriate with the blades and materials.

I have more time than money but I still would not go that route.

 

[samanthad]

After reading this I went blade shopping - a 10” ferrous blades max speed is around 3000 rpm for the Diablo and DeWalt is 1800 rpm. That said, the speed controller above should resolve your speed issues. Finding a 3000 rpm blade with a 5/8 arbor seems tricky.

I guess the question ends up being is a $20 speed controller and a $50 blade and some clamps put you ahead of a dedicated machine, be it a portaband, chop saw, or other tool. Keep us posted on your decision.

Reviewing speed control options I decided against all forms of electrical control to reduce speed outside of replacing the motor. The main reason is that the “reluctance” of the windings when the rpms are reduced results in an increase in current, thus temperature, thus resistance and combined, the temperature will slowly bake the insulation. A stalled AC motor that is not turning will bake and a decrease in rpms with a lower voltage will do the same with the added load decreasing the rpms more. A safer option is to consider a smaller diameter blade and use a ferrous metal cutting blade designed for the material you are cutting in therms of thickness, depth of cut. A 7 1/4 inch diablo is rated at max 5800 rpm, The speed of the teeth at that diameter will be significantly less than the 10” blade rated for the unit. Without modifying the motor you get a speed reduction and less load on the mitre saw. It is possible the blade guard may not be useable and a sled to raise the height of work piece may be needed to cut through with a smaller blade. As well, some blades may be thicker and the arbor lock may need to be modified. You want the blade to be tight, locked, and aligned properly before using

 

[nadogail]

I routinely cut aluminum angle with my 12" sliding Harbor Freight Miter Saw, the carbide toothed blade seems to be very sharp.

 

[dnschmidt]

First, it's a bad idea. Cutting aluminum with woodworking tools is an everyday event. Just use stick wax on a fine toothed triple chip blade and you can cut forever just make sure the work is clamped down. I use DeStaCo clamps and special jigs I've made for this purpose. Steel is A WHOLE NOTHER MATTER! The only safe way of doing this on a high speed chop saw is to use a Lennox diamond blade made for this purpose. They don't cut as well as the carbide tooth ones do at the proper speed (see dry cut saw) but they are a lot safer for what you want to do and they sort of work.

 

[Shiftless]

So is the consensus of opinion that toothed blades cutting metal on a chop saw can be dangerous but abrasive wheels mounted on chop saws are OK except for the abrasive particles flying around and getting into the guts of the saw? No teeth = less or no chance for violent kick back

 

[dnschmidt]

So is the consensus of opinion that toothed blades cutting metal on a chop saw can be dangerous but abrasive wheels mounted on chop saws are OK except for the abrasive particles flying around and getting into the guts of the saw? No teeth = less or no chance for violent kick back

That's about it.

 

[ThePostman]

I have a 20+ year Makita compound slider that I have cut lots of angle and flat steel with. The problem I ran into was the plastic part in the middle of the base eventually deforming, one can find a metal replacement online though....

 

[mv213]

I have made thousands of cuts in aluminum extrusions with a cheap Rockwell miter saw and a high-tooth count carbide blade. No problems. Never tried to cut any ferrous metals with it though, I thought the blade speed was probably too high.

 

[alinc100]

https://www.lowes.com/pd/DEWALT/5002821715?irclickid=zifQiRw4ZxyNTeG0Qm1x72PTUkF01DX1w2tPX40&irgwc=1&cm_mmc=aff-_-c-_-prd-_-mdv-_-gdy-_-all-_-0-_-78091-_-0