Equipment failure at school.

[Bayoublaster]

I've been at trade school and my table is near the drill presses. We heard a loud crash and check out what it was.

 

[Tanguay Custom Knives]

You really have to pay attention to what's going on around you!

I had a 15+ pound vise get flung at me back in 1983. It missed me by about 2 feet. Some numbskull was operating a radial drill press with automatic feed, and about a 3/4" bit without the vise being bolted down. Guess he thought he would just hold it by hand. It nearly cleaned his clock too. It bent that drill bit to a near perfect 90 degree angle.

Had another guy start his lathe with the chuck wrench in the chuck. Nearly stabbed the guy in front of him with a scriber it had sent flying when the wrench hit the bed of the lathe.

Last one- same guy operating the lathe was dressing the wheel of the surface grinder. His dresser was offset on the wrong side of bottom dead center. It sucked the diamond dresser into the wheel which exploded into a million pieces. Unbelievably, no one was actually hurt.

 

[Bayoublaster]

They impressed upon us the dangers of leaving the chuck key in the lathe. Said it can go right throught the back of the head of the guy in front of you.

 

[Tanguay Custom Knives]

I wouldn't doubt it.

I just remembered another incident-
This "kid" was flipping the control of his lathe from forward to reverse over and over again. I guess he liked the sound of the belt squeeling or something. All at once the threaded-on chuck unthreaded itself and chased him around a little.

I can't believe more people didn't actually get hurt! I only actually remember one incident in 4 years of school where blood was actually spilled. A guy grabbed the chips coming off his endmill before it stopped turning. The chips grabbed his finger and introduced it to the cutter. That was a bloody mess!

Watch yourself!

 

[Gollnick]

Wow. Some sort of flaw in the casting, I suspect. But on both sides??? That is odd. What made it suddently fail? I don't know. If we mounted the parts in a SEM (scanning electron microscope) we could probabaly find out. But now you know why a lot of critical equipment has to be x-rayed or otherwise tested.

This is why you sometimes hear that the Air Force spent $150 for a bolt that could be bought at Home Depot for $1.50. Not quite. What you'll often find -- if you can control your outrage and look into the facts of the matter -- is that the Air Force's bolt was extensively tested so that the wing of a plane doesn't do what the table of your drill press did.



I once saw a chuck key go through a piece of ductwork... well, at least through the first wall of it and into the duct. If you leave a key in a chuck in any good machine shop, you will be drawn and quartered by everyone there. I was taught that the key never leaves your hand except to be put back in the drawer (or wherever it lives when not in use).

 

[Bayoublaster]

I forgot to put why it failed. Someone tightened the table too much and snapped the casting. It fell off later when, good thing, no one was near it.

 

[Gollnick]

I forgot to put why it failed. Someone tightened the table too much and snapped the casting.

Even so, to see both sides crack like that... that's very unusual. Normally, you'd expect to see one side crack and fail, but not both simultaneously. Very unusual indeed. I wouldn't blame it entirely on the one guy either. Such a failure could be fatigue coming from many, many cycles of repeated flexing as it was tightened and released. That's what the SEM could tell us.

 

[macdo]

I've spent time working in emergency rooms in industrial areas. Saw enough there to make me very careful in a shop. Flying chuck keys, table saw kickbacks, bandsaw bites. Rollers and particularly augers will kill and maim rapidly. Main injuries seemed to happen when someone removed the safety guard to make the job easier or faster, or when a forklift ran over their foot (steel toecaps don't always helpe here) and when sawing up recycled timber with nails in it. I have a collection of X-rays with nails embedded deep in faces, eyes and heads.
In my garage there are rules and boy do the kids learn them.

 

[GarageBoy]

Sheesh that sounded painful

 

[mete]

Yes industrial accidents can be terrible ,and most are by people not paying attention to the safety rules. ..When I was in high school I learned to operate a lathe.I was taught to always rotate the chuck 360 before starting. That will show a key left in the chuck , clearance problems etc. ...The casting ? Well I might say material failure but in a school it might also be the old " it's fool proof but not student proof " !!!

 

[OwenM]

Yes industrial accidents can be terrible ,and most are by people not paying attention to the safety rules.

No doubt. I worked in a fab shop years ago, and have several stories of people getting torn up for being stupid.
One of our guys was drilling holes in base plates for a 155' log crane(think big hole, thick plate, giant drill press, lots of time involved). He was sitting there, occasionally knocking shavings off with a welding rod. Got a really big one, and decided to grab it and break it off. He was wearing a glove, which hung on the shaving, and got his hand drilled into the plate.

 

[mete]

That's an easy one. In a steel mill big overhead crane with huge electromagnet, man on ground guiding it. Crane operator standing UNDER the load at which time the crane operator accidently releases the magnet !