Exploding cut off wheels

[Robinhood4x4]

This was sent to us at work from our safety dept.

http://www.robinhood4x4.com/UY/UY-Threads/Grinding%20Disk%20Failure.jpg

http://www.robinhood4x4.com/UY/UY-Threads/Grinding%20Disk%20Failure%202.jpg

:yikes:

I believe the guy just got a few scratches and had to change his underwear.

[drguitarum2005]

holy crap! and to think i only wear safety glasses when using a cutoff wheel...

[Dramarama]

Uhmmm yeah... Thats bad mmmkay.

[4runnerchevy]

I have had them come apart but not into my mask. Looks to me like he had the hood down while grinding, is the lense auto-darkening ?, or was he cutting blind ?

[Chapman88SR5]

you can see the floor through the lens so I think its auto. thats nuts!

[Cebby]

That's just a clear lens in the mask. An auto lens wouldn't be that clear. The one with it on him has the dark rectangle p'chopped in (to protect the naive I'd assume).

That's an impressive failure. Something that catastrophic is usually user error though. Twisting the grinder while cutting through stock and binding the wheel would cause that. Also, using a cutoff wheel for surface grinding can cause that sort of failure.

Appears to be a cheap press-board mask too (although I rarely use anything more than a safety goggles or a wood lathe (read flimsy) shield. Kind of makes you want to wear something protective around your neck...

[Seanz0rz]

if you look at each surface of the disk, it appears he was using more that just the leading edge for cutting and grinding... stupid.

using a full face shield is a good idea, keeps the sparks off the face too, but i rarely use it unless i have ALOT of grinding to do. knock on wood, never had one of these blow up on me, but have had PLENTY of the dremel reinforced disks do it. those lil bastards hurt when they hit, this i fear might have caused a potentially fatal injury. he is using a cheap shield there, im sure even a plastic shield would have done better.

hope no one got hurt.

[paddlenbike]

Is now a good time to bring to your attention Harbour Freight's 10-pack of cutoff wheels for $5.99 sale? (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=45430) :lol:

[tulsa_sr5]

OK, i've never had one fail, and i've burned thru a lot of them over the last year, but my dad just had one blow up on him today!!! He's a novice with a grinder, and was just etching some lines in a flat piece to make clean bends.

In the picture, I have to wonder if the guard had been removed from the grinder.

[Bob98SR5]

brian,

yeah thats what i was wondering too. how can the disc fly past the guard, not be deflected, etc?

steve: could you find out more on the how?
bob

[Cebby]

None of my grinders have guards - although mine are all of the 4-5" variety.

The one above looks to be a 7" or 9".

[Robinhood4x4]

I have a feeling this is one of those stories that made it's way through various email inboxes in safety dept around the world because the "lesson learned" was to make sure the person is wearing proper face shield rated to handle such things. In this case, the rating was an Australian rating. So, no, I can't find out anything more about this.

I doubt that anybody who uses grinders everyday, actually keeps the guards on.

Cebby's right, the wheel isn't your normal hobbyist 4.5" grinder.

[4x4mike]

My buddy sent me the same picture, it's from his work. It's a refinery here in the north bay area and the guy was OK. It's a clear lens and the lens area has a photochopped block in it. The picture has been on pirate. I use the 3" cutoff wheels from HF and am as careful with them as I am with any other brand wheel. Use gloves and a mask.

[xonetruthcrewx]

Wow! I have used cut off wheels on angle grinders quite a bit and never had anything like that happen. I only wear my regular glasses also. I too never use a guard on the grinder. Took it off the day I bought it. Haha. Most I have ever had happen was just small pieces (small chunks) taken off the edge of the blade while in a cut. But when that happens I immediately change the blade. The blades are only like a buck fifty each so f**k it right?

[RunnerUp]

damn, thats crazy, i barely use glasses when i cut/grind (bad idea, i know....) maybe i should rethink that approact and start to wear some armor before. i mean, ive had little pieces come off and ive gotten myself a few times, but that would just suck to have one of those come flying at your face/neck region.

[Robinhood4x4]

I'm very careful about wearing safety or sunglasses glasses when I do anything. This includes everything from changing oil to trimming trees to drilling holes to hammering. It would absolutely suck to be blind.

The key is to use glasses that aren't scratched at all. One little scratch and they become annoying and then you tend not to use them. I'm very protective of my safety eyewear and always keep them in at least a ziplock bag to keep the dust off and keep them from getting scratched.

For grinding and chopsaw work, I'll use this face shield
http://www.uvex.us/images/products/shields/bionicproduct.jpg
http://www.uvex.us/products/products_premium.asp?id=11

They say that the majority of people in industry who come in for emergency eye care, were wearing safety glasses, but the object got around the edges. So for higher risk jobs where I can feel the sparks hitting my face, I'll use goggles like this.
http://us.st12.yimg.com/us.st.yimg.com/I/safetyglassesusa_2024_125029762
http://www.safetyglassesusa.com/gb1810st.html

[zombie]

I have a nice scar across my stomach from a broken 7" cutting wheel. After slicing me it went across the room and lodged into the drywall. I was wearing a face mask and gauntlet style gloves and was just thinking about putting on the thick leather welding jacket when it happened. Felt like getting hit with a sledge hammer. I went to the hospital and there was nothing they could do as the high speed cauterized as it went through the skin. Made a nice groove.

[glenyoshida]

I think it was a post TC put up, after seeing the gouge in his face from kickback I started wearing the Face shield over my glasses. In the beginning I also broke a lot of cutoff wheels from lack of experience. There have been many, many times when I pick up the grinder ready to cut only to stop, think about it, mutter some irritated explicative, and put it back down to get the face shield. If I could see a real benefit to not wearing the shield I'd probably consider it but the only thing I can surmise is additional risk and discomfort from the sparks by not wearing it. I also keep the guard on the grinder unless I need to take it off to get the work done. I'm glad to see this post. It's always tempting to leave the mask off just because it's a pain to put it on and work with it at times. Since I can't replace my face and it's an ugly mug at that, I'm thinking a long scar on it might just be the breaking point of causing screams when I walk in the local promenade. lol

[CJM]

Ive broken them before but its all user error. Let the disc cut and dont force it is the key, forcing it causes it to smash apart. I had a 15" metal chopsaw cut off break apart and it flew so far we didnt find the busted off piece, but that was b/c of the way I had secured the metal in there.

[Bob98SR5]

Let the disc cut and dont force it is the key, forcing it causes it to smash apart.


words of wisdom. This goes for any power tool you use.

[CJM]

words of wisdom. This goes for any power tool you use.

Thats basically the cause, you force that disc thats moving at 10k RPM it will shatter..

[MTL_4runner]

It's also the size of the disk because the outside of a 4.5" disk is moving a heck of alot slower than the outer edge on a 7" or 9" disk. So combine this with someone applying leverage to the disk (ie improper use) and you're asking for disaster if you aren't well protected.

[04 Rocko Taco]

I too have no gaurd on my grinder, and I wear gloves and safety goggles if I have a lot of grinding to do, if not, its just the safety goggles. I use the standard 4"-5" grinding/cutoff wheels. I am careful no matter what brand wheels I use, and its usually the cheapies, unless I have a lot of work to do, then I spring for something a little better.

[Cuthroat72]

Sorry to revive an old thread guys, but I just figured I would let you all know a little bit of my history. This EXACT thing is how I got my username/CB handle. I have a '72 Bronco and flopped it. I was using a 4" cutoff wheel to section some of the crumpled body around the wheelwell on the rear of the Bronco, so I could weld in a new lower fender. I had on safety glasses and gloves, and the next thing I knew, I had the wind knocked out of me, and it felt like I couldn't breathe. I bent over to catch my breath, with a hand clutching my neck. Honestly it happened so fast that I didn't even feel it cut, it was more like I got punched. I looked down and where the grinding disk should have been and put 2&2 together. My drop light was shattered. It was only then that I asked myself "Huh... I wonder if I am bleeding." Lo and behold, I already had a T-shirt soaked in blood from my neck to my shirt tail in the same pattern you would find on a baseball player that has slid into base on his stomach.

For those of you that are medically inclined, the cutoff wheel cut all the way thru my sternocleidomastoid muscle (muscle responsible for turning your head, attached at the collarbone and sternum up to the skull, and I nicked the Jugular vein. Being as I was all alone, the phone call I made for help was hoarse, which was less than assuring. Fortunately, I was in the E.R. in 20 minutes, and I am fortunate in that I only nicked the vein, and pressure stopped the bleeding. All I ended up with was about 20 stitches and some discomfort, and I am 100% now.

Safety is vital when using cutoff wheels, and I feel this bares repeating. I would recommend to anyone that you "pop your collar" on your welding jacket and cover as much of your head and neck as possible whenever using a cutoff wheel or grinder. As for me, I am a little gun-shy around anything spinning faster than a ceiling fan :D, but I didn't wait to get "back on the horse". I just wear a welding jacket, thick welding hood, and get as much between me and the cutoff wheel as possible.

Side note: a family friend (surgeon) told me he was going to get me a kevlar turtleneck for christmas.... :rofl:

[glenyoshida]

Thanks for taking the time to post up and another thank you for knowing how to use the search feature. Your personal experience is a great one to share. There are always new people getting familiar with new tools and you taking the time probably just saved someone from a trip to the hospital. I'm glad you reminded me. Sometimes I hesitate and sigh as I put the angle grinder back down and reach for the face shield. revisiting this puts things back in perspective.