Grinding Belt ripped apart - slapped me real hard !!!

J

Jason Cutter

Joined
Oct 9, 2002
Messages
1,419
I wonder if this has happened to anyone before.

I ALWAYS convex grind the edges in by grinding with the edge held down, using the little slack portion between the platen and the convex wheel. Really easy to control and it gives a perfect convex edge each time.

I decided to cut in a straight bevel and decided all of a sudden to grind EDGE UP using a worn 320grit belt. On the second pass on the belt, it looks like the edge got sharp and actually cut into the side of the belt, causing a strip about 1/2inch and 24inches long to tear off.

It ripped the knife out of my hand, dislocating my right index finger (a recurrent problem) and spun the knife into a rubbish pile. The 2 foot long strap of 320grit then proceeded to SLAP ME 20-30times across the head and shoulder region at 2850rpm before I regained composure and turned the machine off.

I did a body check (couldn't find the knife at this stage) and found the shoulder area of my work shirt had been cut open but fortunately no actual cuts on flesh. My goggles and shopoters ear muffs saved my head from more injury than a long funny looking abrasion on my forehead.

I'll never grind edges with the edge up again !!!


HAS THIS HAPPENED TO ANYONE BEFORE ?? Or am I the most accident-prone person in this world ? :( Jason.
 
Happens all the time to me. I dont even flinch any more. It's always exciting when it happens though. My neighbor was over wanting to make a throwing knife. I was demonstrating how to use my 2 x 132 hogger and a 36 grit belt let go. It slapped me across the top of my head and knocked my hat of and left a strip of bloody spots across my ribs and stomach. I just calmly turned off the machine, put on a new belt, turned on the machine and handed him the blank..... It's sill hanging on my shop wall unfinished. Knifemakers have the coolest toys.

Mark
 
Yep, has happend to me a few times also. Gets your attention real quick. I grind edge up and its on a Wilton Square wheel. It usually cant slap you around too much because of the unclosure the belt is in.
 
This is a good arguement for not sitting on a stool or chair while grinding, if you are standing a step to the side stops the pain.

The last one that let go on me left a bruise on my left arm that took 6 months to go away. The face shield that I was wearing prevented damage higher up.
 
Yup, happend to me. I was using some "New Old Stock" belts off of eBay on my Burr King 760 and had a couple let go. That was before my VFD so about 6800 SFPM. Scared the poop out of me.:D Sounded like a gun going off!

It ended up throwing the knife across the room and slapped me in the ear and neck. No major damage to me or the knife. Just a nice "hickey" on my neck.

Haven't had a problem since I stopped using those belts and I always grind edge up, but only against the contact wheel.
 
It hasn't happened yet, but I'm sure it will.

Yahh!! Another shop injury to look forward to. :D
 
I've only been "slapped" by belts in 2 instances (knock on wood) recently had 3 belts pop on my in about 10 minutes (cheap belts from online source :mad:) Had to leave the shop because I was gun shy. The other time was sharpening edge up and pretty much like your scenario, looked for puddles of blood :eek: then found the knife, hammered it into a fence post and left the shop. It does get your attention doesn't it? :eek:
 
Yep, I have had one blow and slap me on the belly while grinding edge up, using my Wilton. It was like a M-80 going off. I Don't remember where the blade ended up, but at least it didn't end up biting me.Belly whelts hurt, by the way! I decided to give it up for the day, belly smarting like hell, and both ears ringing. You got slapped 20-30 times, that had to smart! A guy would get less punishment than that from his wife for buying a new machine or rifle.
 
Just like Gouge said, happens all the time and I don't even think about it, just throw on another belt. I will admit that it happens most when I'm using a belt I should have tossed a long time ago. I can also almost always tell when it is about to go!
 
I always grind edge up and have had two belts bust on me. I inspect the butt joint closely before I put a belt on. This seems to be where my breaks have originated.
 
I froze... :p

My so-called martial arts training has been filed away as "past-life" stuff... I would have / should have sides-stepped the assault of the 320grit belt. Jason. :D
 
Originally posted by Jason Cutter
I froze... :p

My so-called martial arts training has been filed away as "past-life" stuff... I would have / should have sides-stepped the assault of the 320grit belt. Jason. :D
Click to expand...


Good thing you weren't grinding naked, Doctor. ;) :eek:
 
sounds like your was worse than mine... but i did have a 36 grit throw a knife across the room and send my finger smashing against the platen of the grinder drawing a decent ammount of blood from under the nail... took a few minutes of time out before i found a new belt and started at it again.
 
I have had only one or 2 belts let go on my while grinding with nothing too bad happening so far. Is a littel surprising though when they give way suddenly
I wear a hat while grinding just in case to protect the head a little. (as well as dust mask and earmuffs)
What sort of grinder are you using Jason???
Stephen Nixon
http://members.iinet.net.au/~snixon/
 
there's more than one brain cramp that happens here I geuss. :)
two belts and one wheel gone to HeIl ..knock on wood ..
grinding edge up is ok but don't ever sharpen it with the edge up.
or you'll never finish one.:D
 
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