Sherline 1016 5/32" 0JT Chuck with #0 Morse Adjustable Back The P/N 1016 chuck with adjustable backplate brings a new level of centering accuracy to the 5/32" chuck. Extremely tiny drill bits require perfect centering or they are easily broken. By adjusting the front plate in relation to the rear plate which is mounted in the tailstock, perfect centering with the headstock can be achieved. This means your tiny drills hit the exact center of your part every time and do not break due to misalignment. This chuck can easily pay for itself in less broken bits in a short time.