4 3Jaw Self Centering Lathe Chucks + 1-8 TPI Thread Back Plate L

  
SHARS 4 3 Jaw Self Centering Lathe Chucks + 1-8 Back Plate New. For back plate you would not need to drill any mounting holes but you will need to turn the shoulder D1 down. 040 to match the back of the lathe chuck to make the chuck & back plate more concentric with the lathe spindle and reach chuck's TIR. Bolt Circle Diameter: 3.307. Mounting Thread Size T: 1- 8 TPI.

Shoulder Diameter D1: 2.87. Bolt Circle Diameter D2: 3.307. Hub Length C: 0.393'.

Hub Diameter D: 2.2'. Flange Thickness B: 0.63'.

Shoulder boss h: 0.1'. You would not need to drill any mounting holes but you will need to turn the shoulder down. 050 to match the back of the lathe chuck to make the chuck & back plate more concentric with the lathe spindle. When turning the shoulder of the backing plate, ONLY TURN THE SHOULDER OF THE BACKING PLATE WHEN ATTACHED TO THE LATHE SPINDLE.

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. 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.

Clamping Range A-A1: 0.078-1.181. Jamming Range B-B1: 1.181-3.543. Clamping Range C-C1: 1.181-3.150. D2 bolt hole circle dia.

How to process back plate to guarantee Chuck's T. As long as back plate Shoulder Diameter 2.87"> chuck's D1, all 4" chuck will fit in. All back plates have 0.04 allowance, please measure the size of Chuck's D1 before process your back plates. The size of back plates's D1 should be a little bit smaller than the size of Chuck's D1.

Because the gap between back plate and chuck is smaller, chuck's TIR is better. No gap is the best. D1 need to be processed before back plate can be mounted.

040 to match the back of the lathe chuck to make the chuck & back plate more concentric with the lathe spindle. The back plate may come with two or three additional screws (depending on type) for removal the back plate from the chuck.

They are not used to mount the chuck to the back plate, mounting screws should be included with the chuck. 5/16 Self-Ejecting Lathe Chuck Key.