Cast iron back plate finished machined on one side to fit D1-6 spindle nose. The other face and outside diameter need to be machined to suit chuck size.
Cast iron back plate finished machined on one side to fit D1-5 spindle nose. The other face and outside diameter need to be machined to suit chuck size.
Cast iron back plate finished machined on one side to fit D1-4 spindle nose. The other face and outside diameter need to be machined to suit chuck size.