Cushman 4-Jaw scroll chuck

I picked up this chuck for the low price of $0. About 12" and has both independent jaws and a scroll for operating all 4 jaws at once. Has a couple of bruises but operates smoothly.

Anyone have experience with these, good, bad, indifferent?

IME - If the independent jaws are ''tight'' they're not bad, if OTOH they're loose, palm it off on another sucker.

I use a Rohm chuck version built in a similar manner.

Don't expect it to be self centering, but that doesn't mean it is useless. It is still quicker to release than an independent 4 jaw, and it will be closer to centering on the next piece when tightened back up than an independent. But you'll practically have to live with the 'small wrench' in your hand. Make sure that the small wrench has a comfortable size T handle, not the stupid little piece of wire that a lot of chuck wrenches are built with. I welded a 6 inch long piece of 3/4" tubing to mine (3" on each side of the T), makes it a lot easier on the hands to tighten. I basically only use the scroll for release, and rapid repositioning.

I find I can get a little bit more travel out of the jaws than a regular chuck be cause I can split the offset between the position of the base jaws and how far I have the top jaws hanging out past the base jaw. This gives some added support to the jaws that keeps you from winding them too far out of the scroll or having the jaws tilt back when hanging way out. There are times when you don't want to reverse the jaws to chuck on some oddball thing, too, either way, you get to use more jaw travel than any other chuck type.

When you get a nice one, they work really well, at least speaking for myself I like the large jaws.

I have a 6-1/4" that is one of favorite on my toolroom lathe, and a 10". There are different types, some are hollow and/or have a large cavity on the rear, and others and solid and have holes bored out for balance. So, cast vs. machined.

This is the cast type:



This is the solid/milled type:


The solid are typically much better quality chucks, IMO, and the ones I look for.

One advantage with the cast is you can clamp stuff through the slots easier, so I imagine both have their specific use.

I've got a 6" Skinner on a D1-4 that I'll never use. I guess it's OK but your's looks much more stout.

if that's a 12" my old Cushman catalog says its about 140# chuck.

lars66 said:

if that's a 12" my old Cushman catalog says its about 140# chuck.

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Yes my back agrees with the catalog. I can put the 12" 3-Jaw on no issue, the Cushman is going to be a fun.

I will try it out, if it doesn't work well then it will be repurposed.

I bought the exact same chuck some years ago thinking it would be ideal to have on the lathe then changed my mind about all the weight hanging on it. now I have another dirt collector.

lars66 said:

I bought the exact same chuck some years ago thinking it would be ideal to have on the lathe then changed my mind about all the weight hanging on it. now I have another dirt collector.

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Who cares about the weight. Even a regular 12" chuck isn't exactly lightweight. The main thing is whether you need the chucking capacity. I need to be able to chuck anything from 1/2" to 12" on a regular basis, and, I need the 4.125" through capacity.

Last time I checked on a new 12" Rohm, they were something like $5500 (yikes, I bought mine 30 years ago when they were $1500).

What is handier than a 4 jaw combination is a 3 jaw combination, which I also have on my other lathe. That way, I never need to swap chucks

Seriously, a 3 jaw combination is essential for 3 cornered things (like motor endbells) that have 3 cast in chucking lugs that aren't really machined at all to permit rechucking for machining the bearing bores. I can dial in every job to zero runout without fooling around with shims, or settling for 'good enough' with a regular 3 jaw. Even an adjust -true chuck mount is not something you want to adjust every 5 minutes.

Babbitt bearings I would just as soon not wear any more than necessary.

lars66 said:

now I have another dirt collector.

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No you don't - Ebay and find another sucker .think of it like fishing fly and lure manufacturers, .they're out to catch fishermen, NOT fish.