Chuck Safety

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One of the first things I learned was not to take my hand off the key while it was in the chuck. I haven't forgotten that 29 years later.

David

On Thu, 20 Nov 2008 20:06:04 -0800, the infamous Dave B scrawled the following:

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Then you'll come across the magnetized workpiece which disables the machine for no apparent reason... Arrrrrrrrrrgh!

The shield switch soon would be disabled because it's a hassle. The replacement of the chuck key where it belongs is less of a hassle, it's for safety, and it would likely be followed, becoming a good habit in no time. Easier, logical, safe. That should do it.

-- Laziness is nothing more than the habit of resting before you get tired. -- Jules Renard

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I like the solution applied to my old Walker-Turner by its previous owner (unknown). The chuck key is attached to a piece of chain about 2-1/2 feet long, which is screwed to a tapped hole in the headstock. It keeps me from losing the key and if you should leave the key in the chuck and turn the motor on (I never have), the chain wraps around the chuck or spindle and stops everything short before it gets up to speed.

If the key *should* depart the chuck when you turn on the motor, it only gets about one foot from the spindle before the chain brings the key up short.

The way it's arranged, I just drop the key behind the table after using it. Very neat, very handy, and fairly safe.

-- Ed Huntress

On Thu, 20 Nov 2008 22:17:20 -0600, the infamous Ignoramus21542 scrawled the following:

The very same day I bought a spring-loaded chuck key for a drill press is the day I defeated it, since I couldn't take it back. I nearly lost a lobe off the chuck as it slipped out of place while I was tightening the chuck, and that was it. They're dreadful, Ig...Absolutely a pain in the freakin' ass! You've obviously never used one, or the one you used had a -very- weak spring. Most are antithetical to use.

-- Laziness is nothing more than the habit of resting before you get tired. -- Jules Renard

On 21 Nov 2008 04:16:26 GMT, the infamous "DoN. Nichols" scrawled the following:

Then make a better sign:

Zero Tolerance

Due to insurance regulations, anyone caught defeating (or working on a machine with a defeated) safety mechanism will be fired on the spot.

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-- Laziness is nothing more than the habit of resting before you get tired. -- Jules Renard

How about making the switch only operable with the chuck key?

Easy for you to say. Machinists aren't a commodity, you don't get a replacement from MSC. Presumably the guy you just fired was doing an acceptable or better job or he wouldn't be there. Will his replacement be as good? Better a known devil than an unknown one, if you can find a way to work with the known one.

My $.02, Bob

On Fri, 21 Nov 2008 09:37:11 -0500, Ed Huntress wrote: ...

The same idea works well for my drill press chuck key. It's on a short cable, with a swivel near the key -- something like or like the striper leaders at but with a thin cable, plastic-coated, about

2 feet long.

For the truly paranoid worried about chips or a defeat cheat, you could mount a spring loaded plunger on the top, where the plunger hit the switch, and the switch would allow the plunger to 'overrun' a bit.

You'd have to insert the key into the top, push up a bit to gain clearance for lip on the bottom, set the key into the recess on the bottom.

This would keep chips from jamming the switch, and a defeat piece would have to be purpose-built. Too long, it won't go in, too short, it won't push the top plunger up to trip the switch.

That's a lot more work, though!

Dave

For a tamper-resistant system that doesn't require much work you could mount the key from a guard interlock switch on the chuck key. Both mechanical and coded magnetic switches are available from several mfrs. For example:

?ProductID=32

On Fri, 21 Nov 2008 11:49:53 -0600, the infamous James Waldby scrawled the following:

I attached a rare earth magnet to the front of my drill press and the chuck key goes there, in front of my eyes, when I'm done. I have no reason to leave it in the chuck, and have only done so once, about 35 years ago. Noone was hurt.

_Lathe_ chucks, OTOH, can be deadly. Bruce was right in that good machinists don't leave the key in the chuck, anyway.

-- Laziness is nothing more than the habit of resting before you get tired. -- Jules Renard

For the truly paranoid worried about chips or a defeat cheat, you could mount a spring loaded plunger on the top, where the plunger hit the switch, and the switch would allow the plunger to 'overrun' a bit.

You'd have to insert the key into the top, push up a bit to gain clearance for lip on the bottom, set the key into the recess on the bottom.

This would keep chips from jamming the switch, and a defeat piece would have to be purpose-built. Too long, it won't go in, too short, it won't push the top plunger up to trip the switch.

That's a lot more work, though!

Dave

geeez - if you really want to be "secure", just embed an RFID in each chuck key, and a reader on the machine - if the machine's own key isn't in the holder then .... and if a "foreign" ID is detected, machine won't start until the guy from security comes with the safety guy and a triplicate form and they get the computer guy to assign a new key ID to the machine ....

** Posted from **

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Hmm ... I've got a modified key-back retractor with a sliding collar around the Jacobs key on the side of my drill press. (They used to be among the things that GSA carried.) Oh yes -- also the key has a spring around the pin to kick the key out so the key-back can retract it out of the danger zone.

However -- the chuck normally in the drill press these days is a Jacobs version of the Albrecht keyless chuck, so the key hangs there unused. :-)

Enjoy, DoN.

Nice gizmo, Dave.

The single problem that I've encountered with chuck keys/wrenches is not being able to readily see them, or to easily distinguish them from other tools laying around the various machines.

The magnetic key holder on the drill press is a good solution.

Putting some bright colors on lathe chuck wrenches helps by making them more visible. Colored shrink tubing works well for me. When it starts getting grungy, clean it with lacquer thinner/acetone or replace the tubing.

The bright colors stand out in a pile of tools or metal parts, and might help with recognition before hitting the run/start button.

I like the "This machine has no brain, use your own", sign.

Wes

On Sat, 22 Nov 2008 05:20:43 -0500, the infamous Wes scrawled the following:

Aye. 'Tis a good one, lad.

-- Laziness is nothing more than the habit of resting before you get tired. -- Jules Renard

The shield idea makes much more sense to me.

The iteration shown, is only of (limited) use if the shop has only one size, shape or style of chuck key. Even then, it is a lot of work, to provide something that is easy to bypass.

The lathes I use, have, on average, three different chucks at hand, each with a different key. The newer lathes came with a swing over style splash/chip guard, that is interlocked to the power, and have telescopic extensions that allow them to adapt to different lengths of chuck.

We have a couple of these in the shop.

You cant do much about stupid, but you can educate. Whether that means firing a repeat offender, or making that person responsible for the next safety talk or box of donuts, educating the users is probably time better spent, than time spent trying to idiot-proof the machine, which really, can only be done by welding all the moving parts, and encasing the remains in foam rubber.

Maybe post that picture on the safety board. The one of the human remains wrapped around the lathe workpiece.

Cheers Trev

I did the same thing to my drill press, right after it was uncrated & assembled. That was about 10 years ago, and so far it has never been turned on with the key in the chuck. I was going to mount a switch that needed the full weight of the chuck key & chain, but got sick before that happened. That way the key had to be clear of anything, before you could turn the motor on. I also made a foot switch and wired it in series with the existing power switch for the motor. Harbor Freight and other companies sell inline plug in foot switches, but they would turn off the light, as well.