4 Jaw Scroll Chuck with locking screws for using on a lathe with reverse direction. The best selling size from the Charnwood Viper range. A 4″ sized scroll chuck, with the jaws adjusted by a geared mechanism for simple one handed operation. Self centring, high precision design. Ideal for Midi sized lathes and upwards. The fully enclosed design prevents the build up of chips and dust inside the gear mechanism. The standard dovetail jaws can grip the work piece both internally or externally depending on the style and shape of the piece to be turned. The chuck fits directly onto lathes with headstock thread size M33x3.5. for all other sizes an optional insert is required. We also include a wood screw which clamps into the centre of the chuck for the initial mounting of bowl blanks. Supplied with standard dovetail jaws, rear cover plate, wood screw, T-bar 8mm square drive for scrolling the jaws and T-handled hex key 4mm for removing the jaws. Viper3R Specification Direct Mounting Thread: M33 x 3.5 Chuck Body Diameter: 95mm Standard Jaws Expand from: 45mm to 80mm Standard Jaws Contract from: 67mm to 32mm Jaw Travel: 35mm Jaw Scrolling: 8mm Square Drive Minimum Headstock Thread Length: 30mm Weight: 1900g THIS LATHE CHUCK MOUNTS DIRECTLY ONTO A LATHE WITH A SPINDLE THREAD SIZE OF M33 X 3.5. PLEASE CHECK THE SIZE OF YOUR LATHE SPINDLE BEFORE ORDERING. Optional thread adaptors are available to mount this chuck onto a lathe with a spindle thread size of : Thread Size / Part number 3/4" x 16tpi / VIPERID. 3/4" x 10tpi / VIPERIK. 1" x 8tpi / VIPERIA. 1" x 10tpi / VIPERIF. 1" x 12tpi / VIPERIG. 1.1/8" x 12tpi / VIPERIM. 1.1/4" x 8tpi / VIPERIE. M18 x 2.5mm / VIPERIH. M20 x 2.0mm / VIPERII. M25 x 2.0mm / VIPERIJ. M30 x 3.5mm / VIPERIN.