Shars 5" 3 Jaw Self-Centering Scroll Lathe Chuck Solid Jaws + 1-1/2 x 8 TPI Semi-Machined Threaded Back Plate, Machining Required 202-5594-202-6192 L[

Shars 5" 3 Jaw Self-Centering Scroll Lathe Chuck Solid Jaws + 1-1/2 x 8 TPI Semi-Machined Threaded Back Plate, Machining Required 202-5594-202-6192 L[

Back plate needs to be machined in order to fit the lathe chuck A matching back plate would need to be machined on the face and hub OD in order to fit this chuck. For detailed information, please look for the Shars back plate machining guide. If you use a chuck to clamp the backing plate and then turn it, the backing plate will not be true to the lathe spindle and will have more runout than specified when the chuck and back plate are put together. Bolt Circle Diameter: 4.250", Thru Hole: 1.181" Chuck Thickness: 2.28"; TIR (Inch): 0.003" Semi-steel chuck body made from high quality cast iron. Each pinion is ground and hardened to HRC 43. Both sides of the jaw teeth and guides are ground and hardened to HRC 58-62. Each set of jaws are serialized in their own set. A serialized set of jaws are then finished, ground, and lapped on their designated chuck body which will be the same chuck body on the final assembly to achieve a greater accuracy. Before assembling the jaws to its designated chuck body, the jaws finish machining is performed on a close tolerance state of the art CNC machine from Japan. The scroll plate's thread flank are ground on both sides to achieve tighter contact with the master jaw. Each chuck has gone through rigorous accuracy and repeatability inspection by clamping and jamming multiple random testing rods or rings. Accuracy is maintained for the entire clamping range.