3 jaw vs 4 jaw chuck

[thaught]

Can a 3 jaw be as accurate as a 4 jaw when cutting chambers? Would you have a barrel cut knowing it the setup utilized a 3 jaw chuck?

 

[Bret GRAVELINE Graveline]

Yes a 3 jaw can be, just like everything not all lathe chucks are the same, if a lathe is set up with a good buck chuck I would argue its a better setup, especially if set up with soft jaws that have been ground or cut to the same diameter as the barrel shank, A standard engine lathe 3 jaw chuck is not adjustable, whereas a buck chuck has multiple adjustment points that allow the operator to adjust runout, one can adjust runout to absolute,

 

[biednick]

It's not 3 jaw vs 4 jaw, it's scroll vs independent. If you're doing the exact same thing day in and day out a good scroll chuck can be made to work. If you've got variety in your work, like different diameter barrels, independent jaws are the way to go. There's inherit inconsistencies in scroll chucks that can be minimized for a particular diameter, but something bigger or smaller than the chuck is tuned for is going to have more runout. With independent jaws you're effectively doing that tuning every time you mount something.

 

[59FLH]

Once the material is clamped in a 3 or 6 jaw Buck chuck, the chuck body can be adjusted on the back plate like a 4 jaw.

 

[tobnpr]

Assuming you're working through the headstock and not between centers...
Independent 4 jaw, adjust-tru with any number of jaws, or inboard spider. Scroll chuck is no bueno unless you're chambering between centers in the steady rest.