A2-6 chuck with D1-4 spindle

[springer]

What is the swing of the lathe? At some point, going larger actually makes your chuck less capable of holding large parts due to the stick out of the jaws interfering with the ways. My 13x40 lathe (actual swing ~14") gets its widest range of work holding sizes with the 8" 4 jaw that came with the lathe. We are taught that bigger is always better ( ) but that is not always true...

It’s a 1340 but with a gap. I was going to remove it for the large plates I need to turn. And the bigger is better mantra is hard to ignore haha

 

[springer]

Is it the screws or the jaws?
My 4-jaw was tight also.
I took some 800 grit clover (oily) and lapped the jaws by hand in their respective slots- screws removed.
Then after the jaws were moving smoothly with no binding I removed the clover from them.
Then I slathered some on the screws and ran them back and forth with a drill.
de-grease it all, oiled and then all was smooth.

The jaws move freely, it’s is the screws. Or the screws pushing on the jaws into the chuck maybe. I will try some lapping compound or something.

 

[Bob Korves]

It’s a 1340 but with a gap. I was going to remove it for the large plates I need to turn. And the bigger is better mantra is hard to ignore haha

My 13x40 lathe also has a gap, Chinese lathe. The width of the gap is very short, and so watch out for chucks that will be too thick front to back to actually hold oversized work in the gap. I really consider the gap on my lathe to be most suitable for use with the face plate, not with a chuck, except for very thin work, or perhaps something with reverse offset, like perhaps a disc brake rotor. Removing the gap does add space for the oversized chuck jaws to swing in, when holding smaller diameter work, at least near the chuck face.