No matter how safe you are....

[Stytooner]

You can always get bit. They are called accidents for a reason.
Case in point, yesterday I changed the grinding wheel on a Foley Belsaw Sharp All.
It is one I have been using for 6 to 7years.
The cost of these wheels have more than doubled in that time and I use a lot of them. I recently bought a hand held Dewalt 7" grinder to replace the Sharp All for doing this. It actually does a better job of it and the discs are much cheaper and readily available locally.

I only had three more wheels for the Sharp all and was just intending to use them up.

Well, I always wear a full face shield when using this. Upon start up anytime, I stand to one side or the other. Especially when a new wheel is installed.
This time the wheel flew apart almost instantly into about 4 pieces with a little shrapnel as well. About a 3rd of this 1/2" by 8" wheel caught me in my left shoulder as I was pulling myself to the right. It hit the soft part of my shoulder muscle HARD. I don't bruise easily, but it certainly put a frog in there. Gave me a little road rash looking mark about golf ball sized as well. Just a bit sore this am. It's okay.

If it had hit just maybe 1" further right, it would have broken my collar bone. I can just about guarantee that. I was lucky, yes, but safe practices helped reduce the outcome of this injury. I had never had a stone fly apart on this machine, but always practiced start up as if it could.

If it had hit my face shield, it would not have been pretty either.
The spot it chose was likely the best spot on my upper body to have received such a forceful blow with the least amount of damage.

Lets be careful out there guys and gals and always use good safety and machine operating techniques. Now where is that Icy Hot?

[cabinetman]

You can always get bit. They are called accidents for a reason.

I had never had a stone fly apart on this machine, but always practiced start up as if it could.

You were very fortunate. Hope you heal up quick. The key here is being aware of what could happen. Some of that caution comes from experience. Even with that there are those times that the inevitable happens. Who would ever think a stone would come apart? But it did. Its those freaky rare happenings out of our control.

Bad news of the incident, but it's good to bring it up as a reminder.
.

[Uncle Cracker]

Definitely a good lesson to point out, Lee. I am especially careful when starting up anything with a stone wheel, because these can develop latent cracks just from temperature changes or seemingly light shock, and these cracks will be invisible until spun at speed. Even the oscillation from a broken wheel can cause the machinery to throw itself at you.

[Richard in Smithville]

There is a difference between an accident and one from the operators carelesness. We can minimize the danger but sometimes things cannot be helped. That's why we have procedures for just such a possibility. I'm glad to see that you practice safe start-up and that you came out relatively unscathed. It is a good lesson and you set a good example for all who work with tools.

[chopnhack]

I don't own a grinder, but that bit of common sense never occurred to me!! Thank you for the PSA and speedy recovery to you.

[LCHIEN]

Ouch. You going to risk the other two wheels or have you had enough? Even if they don't fly apart on initial startup they are now suspect being the same age and batch and can fly apart at any time...

[Stytooner]

My thoughts exactly, Loring. I have a replacement in the Dewalt. I do have two more, but these will go out. No need to chance hitting one of my CNC machines with another stone. I keep a small 4" wheel on one side for specific jobs. I think I'll just put a wire wheel on the other side.
The grinder wheels have fiberglass mixed in with the resin to keep the wheels from damaging easily. The other wheels were resin based for sharpening blades, but do not carry a mesh inside. I'm now done with them.
I do have other stones I may use, but as always, don't stand in front of them. This thing turns at 5500 rpm I believe.
It was on less than two seconds, so I think it was likely near 4500 to 5000 rpm when it blew.
Absolutely no time to move if you haven't done so already.

[LCHIEN]

My thoughts exactly, Loring. I have a replacement in the Dewalt. I do have two more, but these will go out. No need to chance hitting one of my CNC machines with another stone. I keep a small 4" wheel on one side for specific jobs. I think I'll just put a wire wheel on the other side.
The grinder wheels have fiberglass mixed in with the resin to keep the wheels from damaging easily. The other wheels were resin based for sharpening blades, but do not carry a mesh inside. I'm now done with them.
I do have other stones I may use, but as always, don't stand in front of them. This thing turns at 5500 rpm I believe.
It was on less than two seconds, so I think it was likely near 4500 to 5000 rpm when it blew.
Absolutely no time to move if you haven't done so already.

time to donate the Foley Belsaw to someone on OWWM who will admire it and not turn it on. just how old were those wheels and tool?

[Black wallnut]

As much as I dislike sticky threads this one is deserving. Glad you pay attention to safety Lee as this could have been much worse.

[Ed62]

I agree that it is worth being a sticky thread. It's a good lesson for everyone. Glad you got hit in the soft spot.

Ed

[Stytooner]

Just an image I shot this am.
No pics, didn't happen.

[dbhost]

To say the least, that looks uncomfortable.

I always stand to the side of the grinder when I start it up. Now I'm not familiar with the Sharp All, but I know my Ryobi has a shroud that covers 3/4" of the edge, and nearly all the sides, I try to keep the mouth of the grinder pointing away from my body when it gets up to speed. You never know, a stone could break as in your case, or even a screw or nut could somehow end up in the tray. You wanna take the chance? I don't!

Thanks so much for the reminder.

[GPA61]

Ouch!!! I am glad is was not worse.

[gsmittle]

+1 on the ouch! The fact that a stone could come apart never occurred to me. You can bet I'll change my startup procedure from now on.

On a less serious note, have you sued Foley yet? They should have included flesh detection technology in the stones so the pieces would avoid you.

g.

[Ed62]

Yeah, you were lucky. Could have been much worse. BTW, if this is supposed to be a sticky thread, why is it near the bottom of the page?

Ed