Fits most 8" Independent plain back chuck (please verify the bolt circle diameter and shoulder diameter on the back of the lathe chuck)
This machined back plate is designed to mount onto our 8" 4 jaw independent lathe chuck (p/n 202-5421). The mounting holes to mount the back plate to the chuck are drilled and tapped, and the registration (shoulder) needs to be slightly turn down to match the recess on the back of the lathe chuck.
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.