# Dumb Question About Lathe Chuck Key



## jmarkwolf (Mar 26, 2016)

My new G4003G came with a couple of T-handle lathe chuck keys.

The t-handle is not pressed into place on either (some assembly required) and I'm wondering how much force it takes to press them together. The only press I have is a 2-ton arbor press and it didn't seem to be adequate.

I tried hammering and was worried about bending the handle.

Further, the "ribs" in the handle seem to be trying to "shave off" rather than trying to press into the hole.

I've seen the t-handle on some keys loosen up over time. Is there a tried and true method to assemble them so they stay together without welding?


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## Tony Wells (Mar 26, 2016)

There should be, or could be, a slight chamfer at the edge of the cross-hole to prevent the upsets from being "shaved" off. That they are indicates that the key body may be harder than the handle. You might try just adding a edge break to the hole and proceed on pressing it in. 

I've never seen a chuck key come in two pieces. I guess it saves a little space.


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## Firestopper (Mar 26, 2016)

Follow what Tony says but freeze the handle for a while prior to pressing. Worst case drill it out as close as possible and drill/tap in a setscrew on the end of the body.
Mike the handle to see if one end is smaller than the other for correct sequence (never seen this). Another option is to heat the body prior to pressing the handle.


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## higgite (Mar 26, 2016)

Is it directional, i.e., are the ribs a tapered fit?

Tom


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## tmarks11 (Mar 26, 2016)

strange, my G0709 key came put together.

Freeze the cross piece, put the shaft in the oven and heat it up to 250F, handle with gloves, press it together.

Worst case is you bend the handle and have to spend $12.50 to buy a new chuck key that comes put together.
http://www.grizzly.com/parts/P4003G0006
http://www.grizzly.com/parts/P4003G0007

...or... call Grizzly CS and ask for a replacement.

Dollars to donuts that the chuck key was supposed to come assembled, but the 2359 whistle blew, the worker threw it in the tool chest and ran out the door.... after all, he had to be back at work at 0359, so he didn't want to waste any time...

EDIT: you should have 2 lathe keys; the 6" 3 jaw, the 8" 4 jaw.

Maybe you are trying to press the larger 4 jaw handle into the 3 jaw shaft?


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## TOOLMASTER (Mar 26, 2016)

grab a piece of scrap alum or brass. drill a hole 1/2 way through the size of the handle ...stick it on the end and hammer away


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## kd4gij (Mar 27, 2016)

Make your own  chucks keys to your liking.


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## jmarkwolf (Mar 27, 2016)

Thanks for the input everybody.

Didn't seem to make a difference as to which end of the handle, or which side of the key. Both were just a very tight fit.

It was obviously not a precision chuck key to start with, so I didn't mind abusing it a little. I was able to get the handle in by hammering. Mushroomed the end a little, but it won't ever be coming apart (unless the steel splits)! It will probably outlive me. 

Probably would've been a simple task with a righteous press.

Next task is to fabricate a chuck key safety interlock. I've always been vigilant and have never started a lathe with the chuck key in, but have always been paranoid about it.

Studying the schematic now to see if there's a convenient place to break a connection and insert a micro switch. Maybe recreate the brake circuit as on the bigger lathes.


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## stupoty (Mar 27, 2016)

jmarkwolf said:


> Thanks for the input everybody.
> 
> Didn't seem to make a difference as to which end of the handle, or which side of the key. Both were just a very tight fit.
> 
> ...


 
I See a lot of chuck keys come with a spring on the end to pop them out of the chuck when you let go of them.

Stuart


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## jmarkwolf (Mar 27, 2016)

Update from OP:

The plot sickens.

I just opened the box for the 8in 4-jaw chuck for the first time. It's chuck key came assembled, and has a spring, and fits the 6in chuck.

So my chuck key safety interlock just dropped in priority.


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## epanzella (Mar 27, 2016)

With my G4003G I got an 8 inch key that the rod would fall out of and a 6 inch that was already pressed together and rigid as a welded joint.


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## Chipper5783 (Mar 27, 2016)

kd4 has a good approach.  I've picked up several chucks at auctions (solo or with machines) - usually the key is gone, or a wreck.  I've made 6 keys.  I don't bother with anything fancy to secure the handle - just drill & ream the hole for a nice fit on the t-handle (drill rod), then Loctite.  It looks nice and very clean.


- on the little lathe, the 6" - 3 jaw had no key (but was size correct for the 8"- 3 jaw on my other lathe).  I copied the key from my other lathe.

- on the little lathe, the 4 jaw had a mangled key (roughly hand ground to sort of fit).  I just made it to work well and look well.

- got a collet chuck, no key - I made 2 keys.  I wanted to try a little stubby key, because it takes a lot of turns to install the collet and I figured it would allow me to spin the pinion with one finger (actually works quite well).

- got two 6" - 3 jaws for the dividing heads (one of which is actually part of a spiral milling unit) - neither had a key, and of course they don't take the same size key.  I made sliding handles for them.
http://www.hobby-machinist.com/threads/made-a-new-chuck-key.42346/#post-365824

Chuck squares seem to be rather an odd size (it would sure be nice if they were simply 3/8" or 1/2") - I made all mine to fit with just a little play.  I figure a sloppy key is going to wear/goof up the pinion.


Definitely no little spring or interlocked chuck key holder in my shop (does that make me a bad person).  I don’t really understand the point about an interlocked holder for the chuck key.  I have 6 chucks that I may use (I have 2 lathes, but the same spindle – so sometimes I use the chuck from the small lathe on the larger lathe).  It would seem a little weird to have an interlocked holder for each key, and even an interlock for the 3 chucks that get used more often would be a bit weird.  I'm right picky about never having the key in the chuck unless my hand is on it.  I have never seen the need to leave a key in a chuck.  It takes about 1 second to put the key in, or remove it from the pinion.


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## tcarrington (Jun 2, 2016)

NEVER leaving the key in the chuck is the best habit to get in after you put on safety glasses.


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## MSD0 (Jun 3, 2016)

I can't stand the spring loaded keys. I hang the key directly behind the head and trained myself  to check before turning on the lathe.


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## TOOLMASTER (Jun 3, 2016)

grind a bit off and hammer away...spring loaded sucks...great if you like picking things up off the floor


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## stupoty (Jun 3, 2016)

MSD0 said:


> I can't stand the spring loaded keys. I hang the key directly behind the head and trained myself  to check before turning on the lathe.



Thats where I keep mine, at about eye line height



epanzella said:


> With my G4003G I got an 8 inch key that the rod would fall out of and a 6 inch that was already pressed together and rigid as a welded joint.



I have a chuck key that the handle falls off, it's press fitted, I always have to hammer it back together but then it just falls out by it self.  very odd. 

Stuart


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