Don't leave the key in the lathe chuck

I never leave a key in the chuck even when leaving it for a second. I use 2 keys to dial in a 4 jaw but the lathe power is off and the gears in the headstock are disengaged.
 
  • Like
Reactions: Z2V
That machine don't know or care. Not to long ago on a YouTube there was a guy got twisted up in a lathe spun a bit and fell out. Later on he died from the injuries . Really it didn't look like he was hurt that bad must have mangled him inside. It was tuff to even watch . I've been knocked over by forklifts with idiot drivers a solid tire one mashed my steel toe right through the sole on one foot another time. I'm sure glad they were on .. SAFTEY isn't no toy to play with. Bad enough getting hurt , if it's preventable PLEASE BE AWARE AT ALL TIMES.
 
There was a video of a guy caught on an automatic lathe, ducked under a 2" bar that must have been turning at least 500 rpm. Dead on the second revolution, spun till He was a bag of skin. No one there to shut it off, He was working alone at night. The only way they figured out what happened was security camera footage.
 
Here is an old thread that discussed a solution that one of our members came up with and posted on his website: https://www.hobby-machinist.com/thr...through-the-windshield-of-your-porsche.30440/

The short version is this: He made a chuck key holder from a piece of pipe or tubing. Inside the tube there is a microswitch that is wired into the run/stop circuit for his lathe. In order for the late to run, the chuck key must be in its holder, closing the switch.
 
Done that too, got scaried to die there!
I am an industrial electronic tech.
So all work on my new lathe projecs was stopped immediately to solve this very important safety problem and there is an easy fix for it.
Here goes....
Most machines have an emergency switch or ES "loop" that consist of a circuit comprising the 'mushroom' some limit switches and whatever should prevent or stop the machine if anything is wrong. It is a simple manner to make a chuck key holder where a microswitch will be activated when the key is in the holder. This way, no key? no run!
The idea is just open this loop and add one or two more microswitches in the circuit.
I made mine from wood. The keychuck is inserted in a hole and close the contact when in. I made it to hold both the 3 jaws and the 4 jaws chucks since they are a bit different.
If any of the keys is missing, the lathe will not start, simple, efficient, safe!

I also made a pair of microswitch holders that I can set anywhere on the V-way of the lathe so that when the carriage hits either one (going L to R or R to L) the machine will stop. Guess how I came with this one!
I had once the tool post hit the chuck, this broke the alorris type tool holder.
I also had the carriage bang in the tailstock, this case it broke the shear pins on the drive shaft!
Newbee errors, but dangerous newbee errors!

When I told about tis to my boss at work, he found this quite clever and commissioned me to go around all our machines in the workshop, but also on the production floor to see how I could make the machines safer, more idiot proof.
It took me almost a year to go about the whole plant!

Luc
 
I was a 9 year old when I left a key in dad's drill press and turned it on. Fortunately no one was injured but the chuck (Chuck's chuck?) flew
across the room and smashed into a chemistry experiment that I was working on (a still) consisting of 2 water cooled condensers two
large flasks and a beaker, all glass, were reduced to small pieces as well as cooling water pouring out on the bench and the contents
(very colorful) were smeared all over the wall, bench and floor quite a mess to clean up and financial loss for me. Now almost 70 years later, that same guy still gets a very tight sphincter whenever he hears talk of leaving keys in chucks. My drill press has a short chain on the chuck with a pin that pushes the key out of the chuck when you let go of it. It works quite well and isn't a nuisance to use. My little mill chuck is an Albrecht that doesn't use a key. My lathe came with a chuck key that has a spring wrapped around the square boss but is a pain to use. I use a rube goldberg key consisting of a 10" long 1/2" socket extender with a small ratchet wrench on the one end and the other end fits quite well into the chuck. This works like a charm for my needs. My only other keys fit into the various locks around the house.

Thats how I've stayed grumpy.
 
I'll start out by saying that I like and appreciate EVERY ONE of the "safety interlock" ides that have been presented here. But I've hesitated doing this. I personally prefer to always be conscious and careful, and not get dependent on external devices. Maybe I'm paranoid, but I'm concerned that I could get complacent, especially if if I'm at somebody else's tool that's not similarly equipped.

My good habits were brought home to me one day at work. I was carrying a cordless drill across the production floor, and happened to notice that I was practicing good gun safety - trigger finger placed along the side of the drill, rather than on the trigger :)

Be safe, everybody!
 
I have not yet added an interlock switch either. The key for my three jaw chuck is larger in diameter than the key for my four jaw, and the two chucks use different size square drives, so I would need to make two hangers, one for each key. I still stand by the old habit of turning the chuck, faceplate, or drive dog at least one full turn by hand before starting the lathe.
 
View attachment 252693

This looks safe right??
I cant see how this could go bad at all! I did a similar job where I had welded up some cracks in a spun disk then had to dress down the welds and re polish. Could have held a pin in my backside the entire time. Next time I know its just not worth what I was realistically able to charge.
 
Saw a classmate cut the tip of his finger clean off when he left the chuck key, which was hanging on a chain, in the drill press. He apparently hit the switch before removing his hand from the chuck. At age 15 that message stuck in my head. To this day I will not hang a chuck key on anything. Keyless drill chucks everywhere in the shop. With the lathe I saw and heard it happen shortly after the drill press accident. Got in the habit of never letting go of a lathe chuck key till its in the rack. Like someone said above its a lesson everyone should get but only if no one gets hurt.
 
Back
Top