The PRATT Chucks 9 3 Jaw Self Centering Scroll Lathe Chuck Rear Mount LC51

  
The PRATT Chucks 9 3 Jaw Self Centering Scroll Lathe Chuck Rear Mount LC51. Bore Dia - 2 1/2. Over All Height - 4 1/2. Mount - 7 1/2" Dia x 0.200" Deep Rear Mounted, #.

Key Size - 9/16 Square. Cannot see what you are after...