Abrasive wheel on miter saw

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I want to put an abrasive metal-cutting wheel on a miter saw, to cut mild steel angle with. Most of this will be 3/32" or 1/8" 1-inch angle. Some say, "sure, no problem!" while others say, "the horror, the horror..." The purpose is to cut a few pieces for some welding projects. For example, cutting some angle steel at 45 degrees to make a table top.
Now, before this goes any further, please do *NOT* tell me to "go buy a chop saw" or "buy a used band saw" or whatever. I'm talking about a miter saw ONLY, OK?
There are supposed to be two main issues with doing this:
First, it overloads the motor. But I don't think this would happen, if you just use very light pressure and take your time and go slow.
Second, the shavings/sparks can damage the fence and/or the motor mechanism (bearings). There may be some truth here. The fence shouldn't be a problem, and I can always cover it with something. Particles? Some suggest removing the vacuum. How about attaching the nozzle of my shop vac just behind the blade and letting it catch them? Or maybe putting a big magnet there, perhaps.
This isn't something I'll be doing often. Maybe once a month I'll make 3 or 4 cuts, at the most, no more. As I said, 99% is going to be cutting 45 degree ends in 1/8" X 1" angle, so I can join them together to make a square corner. That's it.
I use an abrasive blade in my circular saw for straight cuts, but it's hard to cut accurate angles with it. I also have a Porter-Cable Tiger sawzall, I don't think that would work well for this kind of cutting, although I've never tried it.
Please give me a tip here, especially if you've actually done it, and aren't just repeating what you've read or heard. And PLEASE don't tell me to "go buy a chop saw"!!!
Thanks, Ron M.
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snipped-for-privacy@austin.rr.com says...

I wouldn't think of it. Buy a hacksaw. A good Lenox or Starrett tubular high tension frame, and a couple Lenox 24TPI bimetal blades. You can make 4 cuts in 1/8 x 1 angle in half the time it takes to change the blade in the miter saw.
Ned Simmons
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Ron,
I was going to tell you to go buy a chop saw, but for some reason I have decided not to ;) Dave Hall
PS - You might want to consider a used bandsaw......
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You beat me to it!!!!
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Ron, The horror! The horror! The only real issue is the RPM difference. A abrasive cutoff saw and more importantly, the abrasive disk is designed for 3200 - 3600 RPM. Most wood miter saws operate from 4000 to 5400 RPM. Abrasive disks do not work well out of their operational range.
As for the project, cutting 0.125" x 1.00" angle with a circular saw (I use a SkillMag77) is a snap and plenty accurate for welding. If you are having problems, the sawzall will also work fine with the correct blade and proper speed. (Slower blade speed than wood)
Dave

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TeamCasa wrote:

In fact they may shatter and do shrapnel damage to many things in the room including. But an interesting idea never the less. Ken
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"the abrasive disk is designed for 3200 - 3600 RPM."
Where are you getting this? Most 7" abrasive wheels have a Max RPM of 6000 to 10,000.
Good advice on here, though.
Ron M.
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Most 12" -14" abrasive wheels are rated for the slower speeds. DAGS If you were going to put a 7" wheel on your miter saw then it could certainally handle the speeds. I go back to my original point, use a Skilsaw, its much safer, faster and cuts accurate enough for welding, if you can weld worth a darn.
Dave

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Assuming that information is correct, the use of an abrasive wheel would be a horrible idea. Over revving abrasive wheels of any kind is a terrible idea. Exploding wheels have a way of killing people. Before choosing to run the setup, it would be a very good idea to verify the speed of the saw to insure the cutoff wheel was run within safe limits. Very nice catch, Dave. That one got past me.
Harold
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Why not buy it precut the way you want it from a local machine shop? They wouldn't charge much for a simple job like this and you have the precision you want and you haven't changed a blade to something that it wasn't designed to do.
Good luck, Rich

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Go buy a chop saw!!!! Harbor freight runs them on sale for $90 or so. :)
I ran masonary blades in my 7-1/2" skill saw as well as some metal cutting blades in both the skill saw and my table saw. Works fine, tears up the bearings from all the crud flying around. I have two cheap Skill saws with loose main shaft bearings in my "do something with or toss" pile. I wouldn't let my good ball bearing Skill saw near an abrasive blade.
One problem you will run into is that use start losing wheel diameter as it wears. On the smaller 7-1/2" saws you run out of working room very quickly. Most of the miter saws are 10" so that is less of a problem. But keep in mind that the chop saws use 14" blades that are MUCH better.
I bought one of the el-cheapo chop saws, switched to some GOOD quality 14" abrsive blades I get at my welding supply place (NOT the HF or HD quality ones!) and get very nice, very quick cuts. I've even munched through a 5" 'I' beam in about 120 seconds
Ron M. wrote:

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I've just spent a few minutes thinking about the rooster tail of sparks that would be flying into my saw, and out of that little DC outlet, and all the plastic parts that saw's got, and I've come to the conclusion that I'm not going to think about it any more. I'm sure it would work but I don't want to experiment with how the saw reacts to it. :-)
Seems like you could cut those pieces with a hacksaw, your tablesaw, or a used bandsaw like Dave says, and then set up a jig for a grinder or sander so you could fine-tune the angle to 45. That's what I'd think about.
No actually I'd think about taking them out to a friend who's got all kinds of metalworking tools but if he wasn't around I'd think about it.
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Go ahead, but first stop and think how much an emergency room visit runs these days. Metal has to be clamped solid before you even think about cutting it. Most wood saws have no useful means of clamping angle iron unless you call those plastic or pot-metal things on the fence clamps. If your blade snags the angle and it flips away from the fence, there will be blood and broken parts. Your saw might be damaged too.
Ron M. wrote:

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How about renting one?
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You are thinking like a real home shop machinist now! Kudos for creativity. Many of us have found that any kind of abrasive saw is suboptimal for home use. They are loud and messy and unsuitable for stock of much thickness. I have had offered to me 2 different metal-cutting chop saws. I brought one home and ran it a couple of times and then gave it back even though it was free to me. Those are really made for cutting metal studs, which are basically sheet metal. They didn't work at all on 1" steel square bar -- I hit a hard spot and it just got harder and in the end the saw wouldn't cut it. The little 4x6" band saws are much quieter, cleaner and safer.
If you want an abrasive saw, you might look around your local area first for a used one. I see them all the time as guys buy them thinking what you're thinking, and then they realize their limitations and then they try to sell them and then they realize there isn't much market so if they're smart then they give them away or really really lower the price. My target price would be $20 or less but only if the saw looked new, and only if I were you.
The market may be different where you live.
You might find the 4x6 FAQ interesting:
http://www.tinyisland.com/4x6bsFAQ.html
GWE
Ron M. wrote:

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Grant Erwin wrote:

...
I use one (14" Makita) all the time for making clean cuts prior to welding...
Good saw and good blade will cut 1/4" mild steel easily...
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Article didn't show on my server, so piggybacking.

[...]
I've done such a thing with a hand-held circular saw, abrasive wheel, bit of wood, and a clamp. I clamped the wood on as a simple guide and held the saw's guide against it. Pressed pretty hard to keep it put. If you can't clamp it on you can probably build a little jig since you'll be doing this regularly. Don't go slow to baby the saw, move fast. If the saw will take it it'll take it. If the saw won't, going slow won't save it since you'll simply spend more time abusing it. I didn't do it often enough to gauge wear on the saw due to dust, but I figure if you blast it out with compressed air when you put it away you'll be alright. Watch the sparks.
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creativity.
basically
hard
little
You might have work hardened the material, or loaded up the abrasive wheel. Everett suggests using a piece of an old abrasive blade, firmly clamped, to dress the wheel. I prefer a band saw, of course, but have cut solid stock with abrasive saws without a problem (unless you count the noise, smell, sparks, etc.!). There is also the fact that some materials are too hard to be cut on a band saw.
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snip---
wheel.
to
Nah! My money says he was using a silicon carbide blade when he should have been using an aluminum oxide one. The reactions he described fit perfectly. Grinding wheels have no respect for work hardening--it just doesn't happen, not as the wheel sees it, anyway.
Wheels intended for masonry are silicon carbide. They should *never* be used on ferrous material aside from cast iron. It does no harm, they just don't cut very long. You can't dress them often enough to make the difference, either. In spite of the fact that silicon carbide is much harder than aluminum oxide, it is easily outperformed by aluminum oxide in ferrous materials because it isn't soluble in steel, very unlike silicon carbide.
Harold
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Thanks I was wondering why I needed masonry and metal wheels for my angle grinder. Karl

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