Flying chuck key... worth preventing?

[TroyO]

I was thinking... it seems a rather common occurance that folks leave the chuck key in accidentally. Is it worth maybe making an interlock or something so you can't do that?

Thoughts of what might be pretty easy... Mount a tube with a switch at the bottom in the control box, the lathe won't turn on unless the chuck key is in the tube. It could be overriden by puttung something else in there but you'd have to know you were doing it, I'd think.

The second idea is to have a rotary power switch that is designed to be turned by the chuck key? (IE... you need to use the chuck key to turn on the switch.)

I dunno, random thoughts of safety... I haven't done that particular stupid thing wih mine yet and I'm kinda dreading it. ;-P

[martinw]

Dear TroyO,

That is a good idea. I read about the idea many years ago, but have not made one myself, despite nearly having a whole bunch of teeth knocked out by the chuck from a large pillar drill. As you rightly point out, nearly everybody will try to over-ride the switch when they are in a hurry.

My humble suggestion would be to make a rough impression of the chuck key from something like epoxy putty, and insert a button switch on the bottom of the moulding. That way, somebody would need to think twice about how to over-ride it.

My two cents...

Best wishes,

Martin

[vlmarshall]

I've seen lathes with a switch just like your first idea, mounted in the SIDE of the T-handle storage tube.
I've heard stories of people killed by a T-handle left in a chuck, and make it a habit to never let go of the T-handle until I've returned it to it's place. A switch would be even safer.

[Rube]

Don't need nothin' that complicated. A simple spring slipped over the key shaft is all it takes. If you get lazy and let go of the key it falls out all by itself. Almost as good as vlmarshall's habit of NEVER letting go of the key until it is where it belongs. Don't need a really heavy spring either.

[vlmarshall]

Ha, yeah, the springs work too. Good point!

I guess I should mention, the stories of lethal T-handles and my nearly-glued-to-my-hand habit are from industrial machines, although I wouldn't want a mini t-handle bouncing off my head, either.

[dertsap]

went to school with a guy who not only left the key in the chuck but he also had his hand still on the key when he hit the clutch ,it wacked his knuckles into the bed quite rapidly , id swear the lathe bounced a couple times before he was able to shut er down ,all the while his hand was wedged , needless to say he was sore for a while

[Geof]

The 'chuck key operated isolating switch' is a very good idea. We have a similar system on a large gantry router where the vises are near the edge of the table and the vise handles interfere with the gantry if they are not removed; the machine will not start until the handle is hung on its hook.

The springs on the chuck key I find sooooooooo frustrating; let go of the key and it falls out down behind the bed where it is difficult to reach.

[hndswthtshdws]

I like the chuck key operated switch idea but it wouldnt work for alot of people. A lot of 3 jaw chucks and 4 jaw chucks use different size wrenches and a lot of people have two wrenches for their 4 jaw chuck.

[Rube]

Originally Posted by Geof ...The springs on the chuck key I find sooooooooo frustrating; let go of the key and it falls out..

Thats kind of the point!!!...you should not be letting go of the key while it is in the chuck. You will be just as frustrated with having to replace the key into the tube after a while. If you can discipline yourself, you really dont need any kind of safeguard, but we all take shortcuts so we have to force the inconvenience upon ourselves.

[Geof]

Originally Posted by Rube Thats kind of the point!!!...you should not be letting go of the key while it is in the chuck....

Okay tell me how to spin the chuck open single handed without letting go of the key.

I agree the best solution is to inculcate good work habits in yourself.

[Rube]

oh, oh, oh...that gives me an idea...LOL
Take the T handle off and chuck the key into a cordless drill...hahaha
you wont likely forget that on there, and one handed operation

[TroyO]

I like the spring idea. So much that I got one the other day and it works just fine. I'm still considering adding the chuck key interlock. Mostly because I'm thinking of a little larger system, using a 12V power supply and some relays.

My though was I could make a magneticly mounted switch that I could use to stop the lathe too, with a dial indicator and such. (Using a couple of "Magswitch" style magnets). It would give me both a dial for depth and a cutoff if it went much past the zero. For the investment of a hacked 12V wall wart and a couple of relays you could add a bunch of intterupt circuits for any use you could imagine.

It's not exactly like some lathes that let you set a point that disengages the auto feed, but it might still be handy for some operations.

Anyway, it would be so easy to do once that system is set up I'd feel kind of remiss if I didn't, LOL.