One-piece increasing jam chuck set. Chuck sizes: three/four", 1", 1-1/four", 1-1/2", 2". 1-1/four" lengthy with 1/four" shank. Works good with cjam10f 5-Piece Forstner bit set to drill out the jam chuck holes. Ultimate answer for securing turning tasks resembling goblets, bud vases, and different gadgets with hole facilities. Insert the robust rubber chuck into your work, then broaden it by turning a nut to safe the work piece.Chuck sizes: three/four", 1", 1-1/four", 1-half", 2" 1-1/four" lengthy with 1/four" shank Chuck expands by turning nut to safe work piece Superb answer for securing small turning tasks with hole facilities Works good with cjam10f 5-piece Forstner bit set to drill out jam chuck holes