Don't leave the key in the lathe chuck

The other story I heard that involved a lathe chuck was about a lathe operator that had overspun a large one on a CNC lathe. Apparently it flew apart and killed the guy. A huge piece of it ricocheted off the concrete floor (after it destroyed his leg) and shot through the roof of the building.
 
I remember the article on the chuck key having to be in it's holder before the lathe will start. Infact I have encountered a second article on the same subject. My only problem with making such a devise is that I have 3 different chucks with different keys. Haven't got over the laziness to build a 3 pronged safety switch yet.
Have a good day
Ray
 
- " I personally prefer to always be conscious and careful, and not get dependent on external devices"
- " 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."

It's OK not to trust any 'external device' they are méchanical per definition so a contact can come out lose, a screw missing etc...
THEY WILL FAIL ONE DAY OR ANOTHER this is why verifying this sort of things should be included in your routine maintenance.

BUT!

The good safety habit you seems to have acquired, as fine as they are, YOU WILL FORGET IT ONE DAY OR ANOTHER! I can guaranty this also.
And that single omission, because you are tired, stressed by production schedule or whatever reason, may hurt you.

So we need absolutely both: acquire the proper habits and reflexes, and install, inspect and maintain a good safety interlock system.
On each machine! The chances that one get distraught and experience a failure of a safety mechanism then becomes about null!

And don't completely trust one or the other, in other words, be weary! I never stand directly in front of the chuck when I start the machine, I never stand in front of the main breaker switch on a new installation and I turn my head away while doing so, wearing leather gloves that goes up to my elbow (here in Canada, our industrial power is 600Vac/3 phases, when you make a wiring mistake, that switch will bark at you in a ferocious display of flames, smoke and explosion! No joke!

Luc

PS: it is a simple matter to make a two chuck keys holder with microswitches in the safety loop... Come on do it!
 
I am just about to commission my ( new to me) bantam 2000, and I like the “chuck key lockout” solution a lot. Firstly, it’s a really good idea to have a place for every tool ( and thus every tool in its place, so you know where it is) but it’s a really good idea to lock out the machine if a key is missing.

I don’t disagree that good, careful practice should be the norm, we are human - we will make mistakes. So it’s not a bad idea to implement safety interlocks for obvious (and popular) mistakes.

Oh, by the way, it’s a good idea to set up any interlock switches so they are in the “machine off” position if they were to come loose, or a wire comes off.
 
Funny, and scary thread. First time I was in a machine shop with some large lathes running I looked at the chuck spinning, the size and weight of it, and the speed, and realized you could get hurt really bad. Then I watched some videos. I don't want to see those again.

A few months ago with I picked up an Atlas lathe I walked into the garage at the sellers house. There sat the lathe, switched off of course, but with the key in the chuck......
 
Took a couple of pictures for my key in the chuck solution. The drill is just a quick way to make major adjustments of the
chuck jaws. Its a small 10" lathe. IMG_8724.jpgIMG_8722.jpg
 
If you make a key holder with a switch make sure it's wired so the lathe
does not start if the lathe is left on when you remove the key. That could
also be very dangerous.
 
I did that in shop class. Luckily it hit the lathe bed. My teacher looked at me and shook his head. I used collets the rest of the year.
 
It just takes training to ingrain in yourself an aversion to certain unsafe things while not depending on your decision making. Having been around guns all my life, I can't even point a toy gun at somebody without getting that quezy feeling in my stomach. It's the same thing with my lathe key. I can't let go of that key without removing it from the chuck even if the power is off. You get in trouble when you start deciding when an unsafe practice is OK and when it's not. If it's never OK you play it safe by reflex even when on auto-pilot (when most mistakes happen).
 
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