OK to use metal cutoff wheels on miter or radial saw? (1 Viewer)

e9999

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I have both a radial saw and a miter saw and am thinking about putting a cutoff disk for metal and possibly masonry on one or both of them. Use would be to cut things like 1/4" thick metal tubing on both and possibly thickish (e.g. 60 mils) sheet metal on the radial saw, although the latter seems a bit iffier.
I imagine it should be fine but to be sure I thought I'd confirm with you tools whizzes.

So, OK to use, assuming max rpm is compatible? Or might there be some subtleties like the motors would overheat, metal dust may damage things, vibrations issues, insufficient protection, or anything less obvious like that?

If OK, any advice about practical use of cutoff wheels in non-specific saws?
 

PAToyota

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First thing is to make sure that the sawdust is cleared out of it before you start cutting metal... ;)

I've got a circular saw that I've used abrasive blades on to cut both metal and masonry on occasion. I just make it a point to clean all the crap out of it afterwards. No way would I consider cutting masonry inside... :eek: So I'm hoping you mean you'd drag the saw out into your yard rather than try it in your workshop.
 

e9999

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my workshop (=garage) is a pig sty, sadly, so a bit more dirt may not matter much in principle but yes, I hear you, some of that dust is nasty stuff. And good advice on saw dust too. thanks.

These abrasive wheels always spook me a bit. They don't look that strong and it could get ugly if one were to to break. I always make a point of not staying right in the potential path of flying debris. Fortunately, never seen one break yet.
 
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I believe metal cutoff wheels like to run higher RPMs than wood-cutting circular saws, but that just means you're going to take longer to cut the piece and you'll thereby heat it up more before you get through it.

I've used an 8" cutoff wheel on a regular 'ol handheld circular saw and it was a heck of a lot faster than a diamond cutting disk on my 4.5" angle grinder. It even worked fine on 1/2" steel.

Another thing: the style of abrasive cutoff disk I'm familiar with has a fiberglass mesh which will generally keep it from 1. exploding, and 2. throwing any big pieces when it does fail. Kind of the same idea as fiberglass/composite pressure vessels and flywheels; instead of throwing shrapnel, they just throw fluff and sandy/dusty junk.

It's not like a solid grinding wheel which will throw large, hard, jagged pieces of the ceramic when they blow.

Whatever you wear to keep from blinding/burning yourself with the sparks will probably be plenty of protection if the disk decides it's had enough, and if you don't actively overhead/bind the disk, or regularly leave it in the rain, it will probably wear down to a nub before it'll ever fail.
 
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Metal cutoff wheels can be VERY dangerous! You don't want any side flex or they can shatter. If they shatter you or bystanders CAN BE KILLED.

Have a mate that was in malaysia getting his yacht repaired and unbeknownst to my mate, a worker 'borrowed' his cutoff blade and installed it in an large grinder and was using it to sharpen a kitchen blade, i.e. side load/flex on the disc. It shattered and killed him instantly. That family lost a husband/father in a fraction of a second. This was a name brand cutting disk (7" size from what I can gather). My mate is still coming to grips with the accident.

cheers,
george.
 
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The spindle bearing on miter saws isn't designed to take the loading of abrasive wheels, so go light on the handle. I used abrasive discs on a Black and Decker miter saw that I got at a garage sale and I used it for 10 years before the bearing went out.
 
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I've never used the toothed style metal blades, but I have used abrasive cut off blades on a Dewalt mitre saw many times. Every piece of plastic on the saw eventually melted, and a buddy caught a dumpster on fire. Other than that it has been slow, but successful.

As for failure of the blades, it does happen, but I've always experienced the abrasive blade "ripping" rather than shattering. The toothed all-metal blades do seem like they could easily become ballistic if shattered at high RPMs.
 

e9999

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mmm.... there is indeed some sort of plastic funnel on mine (Dewalt) that apparently channels out the sawdust. Wonder how that will handle all the sparks.... better check
 

e9999

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The spindle bearing on miter saws isn't designed to take the loading of abrasive wheels, so go light on the handle. I used abrasive discs on a Black and Decker miter saw that I got at a garage sale and I used it for 10 years before the bearing went out.

good point, I can see that as a potential issue indeed
 

PAToyota

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Also depends on how much you plan to (mis)use these tools. With the circular saw, it has been fairly limited. Metal blades for some long sheetmetal cuts where other tools just didn't work well. Concrete blades for making some odd-shaped concrete block cuts. But if I were doing much of either, I'd have likely looked at a "disposable" HF circular saw. Regular use for either and I'd get a real tool. Actually just picked up a Milwaukee abrasive chop saw off with a bunch of blades off craigslist for under $100.
 
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e9999 said:
my workshop (=garage) is a pig sty, sadly, so a bit more dirt may not matter much in principle but yes, I hear you, some of that dust is nasty stuff. And good advice on saw dust too. thanks.

These abrasive wheels always spook me a bit. They don't look that strong and it could get ugly if one were to to break. I always make a point of not staying right in the potential path of flying debris. Fortunately, never seen one break yet.

I had one break into pieces and hit me in the chest. What a bruise it left. No place is safe to stand. When they let lose they go everywhere
 

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As long as the RPM of your miter saw is within the appropriate range of the cutoff wheel, I see no reason not to. Obviously (as already stated) there's always a risk of the wheel failing. My Rigid has a plastic guard over the blade, but I wouldn't trust that to completely prevent something from hitting me if the wheel fails, so I wear my shop coveralls and thick leather welding apron whenever I cut any metal with it.

I used a metal cutting wheel in my Rigid for the FJ62/Mazda seat brackets I built a couple years ago.
 

e9999

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a google search revealed a number of similar questions out there (but of course sadly not benefitting from MUD's wisdom... :) ). Main comments seem to be about cosmetic marring of the saw by sparks and saw plastic being damaged. I suppose that could be addressed (or ignored).

A real cut-off saw is surely a better way to go, likely all metal and stronger guards, but I'm running out of space and would not be cutting much steel anyway. Heck, I really don't have the room for the miter and radial arm saws either but they're just too much fun to play with occasionally... The miter saw does a fine job on aluminum actually (with a carbide blade).
 
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Aren't the standard miter saws for wood and metal the same?

I guess one could run faster, but I haven't seen a difference between the two.
 
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I got the idea to do this with my almost new Ridgid miter saw. It destroyed the plastic insert on the base of the say and the degree indicator on the back. Saw still works but won't ever be doing that again. :bang:
 
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I use one on my miter saw for light stuff square tubing stuff like that. What i noticed is that the cast off gets hot! Duhhhh and it melted the plastic backing of the cheap miter saw i was using. No big deal still cuts true 90's and 45's but its going to mess up your saw. Also those disks shatter, so use the safety guard and don't be in a hurry. Gloves, eye protection, and a leather apron or wielding jacked. Danger never takes a holiday.
 

TallCanDan

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The plastic insert on the table of the saw, where the blade dips into, should be removable on most saws. This is a replaceable wear item in case the blade should contact it. Removing it to cut metal won't affect any parameters of the saw.
 

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This is a replaceable wear item in case the blade should contact it.

You would think. We have a really nice Delta miter saw that we bought in 2006, that plastic insert is pretty beat up now. No longer available, even on ereplacementparts.com. :mad:

I would be VERY reluctant to cut metal on a radial arm saw. I had one for many years, used it a lot, and I've had that thing fling hunks of wood across the shop many times. It would be worse if it was flaming hot razor-sharp hunks of steel. If you look at how they operate, the cutting motion of the blade if you are using a push-motion tends to cause the work piece to get lifted up off the table and away from the fence.
 

TallCanDan

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KLF said:
You would think. We have a really nice Delta miter saw that we bought in 2006, that plastic insert is pretty beat up now. No longer available, even on ereplacementparts.com. :mad:

I would be VERY reluctant to cut metal on a radial arm saw. I had one for many years, used it a lot, and I've had that thing fling hunks of wood across the shop many times. It would be worse if it was flaming hot razor-sharp hunks of steel. If you look at how they operate, the cutting motion of the blade if you are using a push-motion tends to cause the work piece to get lifted up off the table and away from the fence.

Sucks about the plastic piece!
I agree with not using the radial arm saw for reasons you mentioned. I think there is way more control to a chop saw.
 

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