P3PPY
P3PPY SuperDork
6/17/24 10:33 a.m.

I've heard a couple horror stories about using cutoff tools and having discs explode. I've even had a couple near-misses myself. What's a good tool to use instead or some tips to stay safe?

Trent
Trent UltimaDork
6/17/24 11:07 a.m.

1. Keep your guard on your grinder! Seriously. Most folks I know swear they get in the way and pull them off, but they are great at controlling where you cast your swarf, keep you cleaner, and protect you.

2. Inspect your discs for damage. Grinders get dropped and chip the edges of the wheel. It unbalances and weakens them

3. When you are using a 0.050" thick cutoff wheel, keep the grinder straight. Twisting the thin blade when it is buried in the workpiece is what shatters them.

4. Don't cut aluminum with a standard disc. There are special discs for aluminum. Also a bar of soap or wax will help. The aluminum builds up on the wheel and unbalances them and at 30,000 RPM that spells rapid disassembly.

 

I am sure there are more. Just wear eye and ear protection. 

 

adam525i
adam525i SuperDork
6/17/24 12:09 p.m.

What he said! For eye protection I like the full face shield as part of a cutoff wheel lodged in your cheek doesn't sound fun either.

I'd add be aware of where the sparks are flying as they can damage things (I ruined a side window on my car as the hot, molten sparks embedded themselves into it) or start fires.

The great thing about angle grinders is they're cheap and versatile, the con is the danger with them which all of the above helps with. For myself working in a small garage I did a lot with an angle grinder but recently got a Harbor Freight porta-band and their horizontal/vertical stand for it. For anything I can do with that it is significantly safer and quicker than the angle grinder.

1988RedT2
1988RedT2 MegaDork
6/17/24 12:39 p.m.

I don't know about horror stories.  I do know that the discs WILL explode, and I plan accordingly. 

P3PPY
P3PPY SuperDork
6/18/24 2:22 p.m.

Is brand of disc relevant?

1988RedT2
1988RedT2 MegaDork
6/18/24 2:28 p.m.

I find that with consumables in general, you get what you pay for.  Saw blades, grinding wheels, sandpaper, drill bits.  The good stuff just works better.  Norton, 3M, etc.

Spoolpigeon
Spoolpigeon PowerDork
6/18/24 2:31 p.m.

I had an accident a few years ago with a death wheel where the disc started to come apart and it bucked the grinder out of my hands and into my thigh. It was a nasty deep cut that required a bunch of internal stitches (ouch) and about 18 staples at the top layer. I had the guard on, but it could have been worse if it wasn't there.

 

Go slow, don't force the cut. Let the tool do the work.

Use the extra handle thingy if available for a better hold on the tool.

If cutting something in half or cutting to length, support the material on one side near the cut so that the material doesn't fold and try to pinch the spinning blade.

I also try to stand slightly off to the side. That way if the blade comes apart it won't be on the same plane as my face.

STM317
STM317 PowerDork
6/18/24 2:40 p.m.

Oscillating tool with the right blade might work depending on what you're cutting.

Same could be said for a sawzall type reciprocating saw.

Boost_Crazy
Boost_Crazy Dork
6/18/24 2:45 p.m.

I'll add that a metal cutting circ saw is way safer, quicker, and cleaner than a cut off wheel. 

Toyman!
Toyman! MegaDork
6/18/24 2:51 p.m.

I've been running grinders with the guard on for as long as I've owned grinders. Call it 20 years. The guard has never kept me from doing a cut. Keep it on. 

If your grinder does not have a toolless adjustment for the guard, buy one that does.

Do not have your head in line with the plane of the disk.

You can watch the cut line from the guard side of the wheel. Do so.  

Make sure what you are cutting is fasted down and use two hands on the machine. Disks shatter when the tool jerks and puts the disk in a bind. I don't care how strong you are, you can not hold the material in one hand and the grinder in the other. You will shatter a disk doing so. 

Do not force the cut. Let the tool do the work. Too much pressure puts the disk in a bind. Bound disks explode. 

Don't drop the grinder. If you do, inspect the disk for cracks or damage to the edge. If in doubt, change the disk. They are much cheaper than sutures. 

Buy disks by the box. If you have 25 of them on hand you are less likely to run that slightly cracked disk for that one last cut. 

 

akylekoz
akylekoz UltraDork
6/18/24 3:00 p.m.

Not sure what to say, I have never had one blow up on me.  I'm not exactly careful or nice to them, maybe I use high quality discs, looks like I use Norton brand.

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