What the Chuck?

ja762 · Feb 4, 2018

This 4-jaw chuck which came with my recently purchased South Bend 13 has me puzzled.
It is 12 1/2" in diameter, which is too large to be of any practical use that I can see, which might explain why it looks like it's never been used. Am I just being dense, is there's some use for this thing I'm not aware of? You can only clamp a four inch piece in it before the jaws hit the ways, while you can clamp an eight inch piece in the 10 inch chuck.
I would like to sell it and put the money back in my lathe, but I need to figure out just what I've got and who's going to be able to use it. I can find no markings on it whatsoever but the paint exactly matches the original SB paint, not that that means anything, and the back plate appears to me to be original.
Thing is, if this is too big to use on a 13, and (as far as I can tell) all of the larger lathes have larger spindles, then why would they sell a chuck with a 2 1/4-8 back plate when the damn thing is too big for any of the lathes that take that size spindle? Are there larger lathes that have this size spindle that I'm not aware of?

Renardiere · Feb 4, 2018

A large 4 jaw chuck can be useful mounted horizontally on a rotary table on a mill. Don't need to keep it for the lathe.

Brodytonelotti · Feb 4, 2018

I agree it is too large for that lathe. However it is larger and has more mass so once it gets moving it has more momentum so you can take a little bit heavier cut. Also if you reverse your jaws you can probably hold about a 9” piece. I don’t know if your 10” chuck has the t slots on the face or not, but if it doesn’t then you can use the 12” as a large face plate if you take the jaws out.

ripperj · Feb 4, 2018

Hard to tell from the pic, but that backplate looks kind of light for that big a chuck. Might be something that was put together for some particular use, from parts not usually together

Sent from my iPhone using Tapatalk Pro

Adwcali · Feb 4, 2018

Looks like a newer chuck not an original Southbend. Most likely a previous owner put it together not knowing any better.

Monarchist · Feb 4, 2018

ja762 said:
...why would they sell a chuck with a 2 1/4-8 back plate when the damn thing is too big for any of the lathes that take that size spindle? Are there larger lathes that have this size spindle that I'm not aware of?

View attachment 219561 View attachment 219562 View attachment 219563 View attachment 219564

No sins in the metal, here. "They" almost certainly DIDN'T sell it that way.

Backplate was never told in advance that some local optimist would mate it to an oversized chuck.

Pull the backplate. It fits YOUR spindle. Use it to mount something more useful.

Peddle the chuck as a bare flatback, and some Pilgrim with a 16" or better lathe won't have to care it ever had the small mount back of it.

Danny VanVoorn · Feb 4, 2018

As Monarchist said, you can put any back plate one needs on that chuck. Another thing is the grip starts going down hill the farther the ends of the jaws stick out of the chuck.
One thing you can do with the 10" that can't be done with the 8" is put a 3" diameter piece all the way inside of it. To me that makes a lot of difference on some jobs when I'm cutting a lot on the end? Just my opinion.
Dan

ja762 · Feb 4, 2018

ripperj said:
Hard to tell from the pic, but that backplate looks kind of light for that big a chuck. Might be something that was put together for some particular use, from parts not usually together

Sent from my iPhone using Tapatalk Pro

Actually the backplate is pretty beefy. It's 8" in diameter and 5/8" thick.

ja762 · Feb 4, 2018

Monarchist said:
No sins in the metal, here. "They" almost certainly DIDN'T sell it that way.

Backplate was never told in advance that some local optimist would mate it to an oversized chuck.

Pull the backplate. It fits YOUR spindle. Use it to mount something more useful.

Peddle the chuck as a bare flatback, and some Pilgrim with a 16" or better lathe won't have to care it ever had the small mount back of it.

The backplate is 8" in diameter. I don't have a faceplate for my lathe, I was thinking I could make a small faceplate out of it, or it that a crazy idea?

ja762 · Feb 4, 2018

Brodytonelotti said:
I agree it is too large for that lathe. However it is larger and has more mass so once it gets moving it has more momentum so you can take a little bit heavier cut. Also if you reverse your jaws you can probably hold about a 9” piece. I don’t know if your 10” chuck has the t slots on the face or not, but if it doesn’t then you can use the 12” as a large face plate if you take the jaws out.

That's the one thing I was thinking about. At 100 lbs. that thing has so much mass that once you get it spun up it's going to be a lot harder to slow down. If you are working with hard to cut materials or, as you said, want to take heavier cuts, it would have to be an advantage.
With the jaws reversed it will hold something 9+", but the grip range is only 5/8 ".

ja762 · Feb 4, 2018

Danny VanVoorn said:
As Monarchist said, you can put any back plate one needs on that chuck. Another thing is the grip starts going down hill the farther the ends of the jaws stick out of the chuck.
One thing you can do with the 10" that can't be done with the 8" is put a 3" diameter piece all the way inside of it. To me that makes a lot of difference on some jobs when I'm cutting a lot on the end? Just my opinion.
Dan

The hole in my 10" chuck is almost 3 inches, while the 12 1/2" is just under 4", so I guess there is that. It'll only hold a four inch piece before the jaws hitting the ways, but you can slide that piece back in a lot further.

Monarchist · Feb 4, 2018

ja762 said:
...will hold something 9+", but the grip range is only 5/8 ".

Always tried to avoid clamping anything as would move anywhere near that much, once in the cut.

"Overshoes" for the jaws can be fabbed.

Too bad it dasn't already have the serrated style two-piece jaws as limited range power chucks rely on to set up for their best grip.

rbdjr59 · Feb 4, 2018

One day you are going to be glad you have that chuck. Turn those jaws around and use it. That step gives you a good back stop and will hold more than that little lathe will ever pull out. It greatly increases the capacity of your machine. Just watch your clearances.

jim rozen · Feb 4, 2018

You can do little stuff in a big chuck, but you can't do big stuff in a small chuck.

The chuck spins over the ways, by definition it fits the machine. You won't use it often
but there are times when it's a must-have. My 10" lathe has an 8" six jaw that 's too large
for the machine. But I use it at least three times a year.

thomasutley · Feb 4, 2018

If it’s in good shape, I could be the Pilgrim that Monarchist is referring to above. It would be an occasional nice-to-have on my 16” if the price is right and shipping cost doesn’t kill the deal. You would keep the backplate to use with your next chuck and I’d make one to fit mine.

If you’re otherwise attached to it but don’t want to use it on that lathe, I’d keep it for mill use or as a rotary weld positioner.

PM me if you decide to part with it. I’m in no hurry as I’m still finishing my own restoration.

Monarchist · Feb 4, 2018

ja762 said:
The backplate is 8" in diameter. I don't have a faceplate for my lathe, I was thinking I could make a small faceplate out of it, or it that a crazy idea?

Half-baked, is all. Whatcha want is two or more round discs "Blanchard ground" to make sub-plates to make it INTO a flexible faceplate. IIRC, several vendors on the 'bay as carry those plates in various ID and thickness, often in ignorant A36 structural steel. That works OK. You can use drilled and tapped holes for fixturing "whatever".

Even so, better to use it for a chuck. 12 1/2" was too f*****g big, TEN inches is clumsy, but far more usable.

You have to think about whether you can make use of (more) 6-Jaw, 4-Jaw, 3-Jaw, 2-Jaw. I also have a magnetic chuck, but cannot recommend those for general purpose use.

W/R "Proper" faceplates:

Tee slots only come in exactly two varieties on bespoke face plates, anyway:

- Wrong location to be of-use

- In the damned way.

WHEN you find a "proper" faceplate, it should be an integral mount - made for your spindle nose and thread, no separate backplate utilized. That avoids mounting bolts being where they are a problem, and it allows a shorter overall length.

Try, and try HARD to not drill a faceplate. Sub-plates work on bespoke faceplates, too, and not all jobs require that they be steel, nor even metal.

johnoder · Feb 4, 2018

It IS a face plate. See those tee slots?

Danny VanVoorn · Feb 4, 2018

ja762 said:
The hole in my 10" chuck is almost 3 inches, while the 12 1/2" is just under 4", so I guess there is that. It'll only hold a four inch piece before the jaws hitting the ways, but you can slide that piece back in a lot further.

My bad; I was thinking about what I have and typing about your situation, I have the 8" and 10" chuck and you have the 10" and 12". It's a similar situation though and I think you got the point I was making, it's better if you can get the whole depth of the jaws on a part instead of just that inch or so proud of the chuck face.
Dan

ja762 · Feb 4, 2018

Danny VanVoorn said:
My bad; I was thinking about what I have and typing about your situation, I have the 8" and 10" chuck and you have the 10" and 12". It's a similar situation though and I think you got the point I was making, it's better if you can get the whole depth of the jaws on a part instead of just that inch or so proud of the chuck face.
Dan

I figured as much, but there was no sense in pointing it out since your point was valid either way.

ja762 · Feb 4, 2018

Monarchist said:
Half-baked, is all...
12 1/2" was too f*****g big, TEN inches is clumsy, but far more usable.
Tee slots only come in exactly two varieties on bespoke face plates, anyway:
- Wrong location to be of-use
- In the damned way.

But, half-baked is what I do best... :nutter:

I didn't realize until I was looking in the catalog earlier that SB recommends a 7 1/2" chuck on the 13. It makes that 12 1/2" look even sillier. I suppose an 8" would be easier to work with, than the 10" I have. I'll have to put an 8" chuck on my "to get eventually" list.
Though I haven't even used one yet, I keep looking at the tee slots in faceplates and thinking what are the chances those are going to be in the exact positions I need them? I suppose I'll find that out as I go.

What the Chuck?

Aluminum

Aluminum

Aluminum

Stainless

Aluminum

Diamond

Titanium

Aluminum

Aluminum

Aluminum

Aluminum

Diamond

Cast Iron

Diamond

Hot Rolled

Diamond

Diamond

Titanium

Aluminum

Aluminum

Similar threads