The 4 jaw chuck is the most versatile of all the chucks. It can hold round and square shaped materials. Unlike the 3 jaw chuck (self centering) each jaw on the 4 jaw chuck is adjusted independently of the others.

Some features of the 4 jaw chuck are

-   Hardened steel jaws with steps
-   Reversable range 1/8 to 3 1/4 inches
-   Jaws are independently adjusted in pairs
-   Setting a workpiece off center creates crankcase and cam shapes
-   Parts may be machined to run very true (this will require more time to center than a self centering 3 jaw chuck)