My First Belt BLow Up -

Joined
Mar 29, 2002
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4,591
I have had belts split and tear at the edges before and that is attention getting. Tonight I experienced my first belt blow up. It sounded as if the entire grinder had dissentigrated and the blade had snapped into pieces. What a bang it made. The belt snapped in two and missed me completely. The only harm it really did was bang the blade a little but the blade was in early stages of grinding so nothing was comprimised. I know now it was my fault because I had the grinder up pretty high and I was really leaning into it. But I gotta tell ya, it is an experience to have a belt blow up - one I am not looking forward to having again very soon. I do know I was very lucky. I remember Fitzo telling us about his last grinder fault. So far the worse I've been hurt by a grinder is to cut my finger in half by swinging around to hear the phone ringing while the belt was rolled over the wheel.

RL
 
I guess it wouldn't have helped in this case but the more I read stories like this the more I think you guys need to make gaurds that will cut a split belt as it comes around.
I've read about guys have them split vertically up the middle and slap them in the face 2 or 3 times. If you put a blade or probably even just a thin gaurd that sat about an inch above the belt, parallel to it, with the cutting edge opposing the belt direction it could snag those flaps and hopefully cut/rip them before they came around to hit you.
 
i have had belt failure a couple of times. Now I wear a full face shield and a leather apron when I grind. Feel especially safe when grinding at high speeds.

Marcel
 
I have had three or four 800 grit belts explode on me. Sounds like a shotgun going off in your face.

Luckily, I have not been hurt (only my pride when I had to explain to my wife how those racing stripes got into my drawers :eek: )

Had one 400 grit explode and knock over a couple of gallon cans on the workbench close to the grinder. Scary, Scary, Scary sounds and sight.

I was pushing them too hard..........I sometime get impatient when doing those finer grit grinds.

I remember muttering to the grinder, "earn your keep, earn your keep" when..............BOOM.........It talked back saying "lay off boy". :) :)

Robert
 
this is kind of funny, I ws going to post about it before but never did..
I was using Don Bell's grinder, he was trying to show me some tips for grinding, he took out a small bar of O1 and took a pass, then got me to try it the same as him. His grinder was much much faster than mine and I wasn't used to the power it had...
the second time I went for a pass, as soon as I hardly touched the steel to the belt it blew up, shot across the room just hardly skimming across the side of my head.... I shat my pants :eek: :eek: :eek:

I looked at Don thinking he was going to be mad as hell, but all he could say was "do you have all your fingers?!?!"

I started to laugh but still thinking he might be a little mad I kept it at bay.

I still laugh about it every time I think about it, man that scared the crap out of me! :D

sorry about your belt Don!!!

hopefully you're laughing about it now too. ;)

Steve
 
Glad you weren't hurt, Roger. Quite an adrenaline rush, eh?? ;)
 
Roger, I'm glad you wasn't injured, and the blade is ok! I had one blow on me, so I let the belt massage my tummy in rapid order. I was wearing a cotton shop apron at the time, and it was cut up, but my tummy was just bruised and welted. It was like being ringed by a 12GA in the duck blind, too. One other thing, did you see the huge cloud of dust when it happened?
 
Ray, yes. It was the the D2 :o .

Hey guys, I really prefered not to say it up front but I was wearing nothing but my Fruit Of The Looms. That is my traditional grind. The only way it seems to turn out well for me. I do taper tangs with jeans on though since I always do that at full scream. Maybe my lady could get me some leather under wear for Christmas(?).

RL
 
John, I know better than that. Your gut can't stick out more than this ol'beer belly.

I have no idea why the belt went straight down to the floor without whipping me first. It was a J-Flex and and that may have helped. If it had been hard backed I might have gotten my thingie stung.

RL
 
The first time I had that happen, it was one of the then new 15 micron belts. Sounded like a .45 going off in my face. Scared the hell out of me, but no harm done.

The most recent time was just a few months ago when I had a student over grinding.
The belt started to sound funny and I went to push him out of the way but he resisted, and the belt blew at that instant. There was no time to say anything. Made a believer out of him.:eek: :) . The belt was shredded at the joint, and no one was hurt.

I'm glad to see you weren't hurt.
 
Yeah Mike, I hear ya. Mine didn't even break at the tape. I was grinding down too (away from belt flow). I don't know just why she blew up except that maybe I was dogging her too hard. It just busted clean across, no splits or shreads. She just busted clean. My leason, unless someone can advise me better, is more patience in grinding. I'm already too slow as it is.

My single largest expense in making knives is cost of belts - by far.

RL
 
I've been grinding for over 20 years and have only had 4 or 5 belts break on me.
I've got to ask: How much tension are you applying on the belt?
What brand of belts are you having problems with?
How hard do you push?
And do you deform the belt?

Most manufacturers would ask the same questions. And pushing hard will "deform" those crisp grinds by changing the surface contour of the contact wheel.
Oh, yeah, what hardness is the contact wheel? Most of them are way too hard in durometer, and that chews up belts at their weakest point. You have to special order soft contact wheels these days.

I don't know about you guys, but what works for me is to let the belt do the work without pushing hard. That prevents slips, faceting the grinds, and contour/radius variations in the grind face.

Also speed is a question...
 
JayFisher said:
...................Also speed is a question...


I never did get any good results from grinding at warp speed.
When I got my first belt grinder in the early 80's, I had to grind at high speed, it's all that was available.
By 1985, I was able to get a Burr King Variable, and it was like heaven.

I've found that I can grind way faster at lower speeds, with less chance of error just letting the belts do the work. The material seems to be removed much faster at slow speed than at high(at least with 40-60 grit belts).

Some people report just the opposite, but that is my experience.
 
Roger, with your typical grinding apparel, you're going to have to always make sure to not get too excited as you grind. ;)

Wait'll IG sees this thread..... :eek:
 
Yeah, I need one of those chastity belt things.

It was running pretty fast and the belt was worn. The platen being used is pyrocerim.

RL
 
A few years ago I ordered some off brand discount abrasive X weight 50 grit belts. They were pretty cheap and advertised to equal Norton, so I bought 10 of them to try.

I had previously profiled a blade and had the hollow grinds pretty well done when I felt like I needed a fresh belt(besides I wanted to try the new belts). The new belt blew with in the first few seconds of grinding. When it blew it jerked the blade from my hand and slammed it into my chest with enough force to drive me back a couple of feet and put me on the floor! (some of this may have been just my reaction to being hit???)

The blade had hit me edge on, tearing through my shirt and leaving a cut about 4" long and nearly to the bone directly over my heart. Had it hit me point on it surely would have killed me!

Needless to say the other belts went into the fire and I will NEVER use an off brand discount quality belt again!

Cheap belts just aren't worth the risks.

Mike
 
WOW, Micad, that was an especially scary one.

Last week I recieved a box of 20 new belts from the company I've been buying from for a while (A&H Abrasives). The first 40 grit broke/blew up within a couple minutes of grinding. I was wearing my full face mask and a wool hat, so thankfully no damage done except for a mild heart attack. It felt much like it feels to get kicked in the head wearing a sparring helmet. Anyway, theh next belt broke after about 15 minutes of use, and then the next soon after that. Long story short, I went through 6 belts in one day. When I called the company they were SUPER nice and apologetic. They said they had a new guy there who was accidentally taping the belts without doing something that he was supposed to. She replaeced my entire order for free. Good customer service...

Anyway,this order wasn't the first time I've had this happen, and I'm sure it won't be the last. I just make sure I'm protected as well as possible and hope that I don't bite it too hard next time...
 
Glad you weren't hurt. That must have been scary. :eek: In a case like that, there's no time to react. You're like a target for that belt, for wherever it wants to go. :eek: I'll be more careful as sometimes I like to grind naked, especially in the summer. :eek: :D Seriously, the only situation I've had was on the buffer using a sisal/cloth buff, as it's wearing down it frays and a piece of it flew off and hit me in the throat, OUCH!
Scott
 
I've been lucky Rodger. I haven't had one blow for a couple of years. The ones I did have blow up were on some of the early grinders I made. It was then that I realized the manufacturers did some things for a reason. :D

If you really want to scare yourself, make a large slack belt grinder with a stepped up 5hp motor and use cheap belts while really leaning on the work.

The thing not only goes off like a shotgun, you fall in the direction of the broken belt if you are leaning hard enough! :o

Remember my motto : Safety First! :rolleyes: :eek:
 
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