Using the Easy Chucking Screw, double-ended worm screw, is one of the fastest and simple ways to begin your turning. The exclusive and *patented double-ended design allows you to mount a wider range of workpiece sizes without the need for additional chucking screws. Screw threads are 3/8" and 1/2" Diameters. Fits most 4-jaw chucks. Easy Chucking Screw is included as standard equipment with Easy Chuck™. 100% Made in USA.    *Patent No. US D753,477