The SIP 4" Chuck 3/4" x 16TPI for Wood Lathes is a heavy-duty 100mm 4-jaw and self-centering chuck designed for expertly clamp a workpiece safely and securely, perfect for turning on the other side of the workpiece and various other applications. 100mm 4-jaw self-centering chuck Comes with interchangeable jaw sets Heavy-duty screw chuck design included Supplied in a heavy-duty storage case Ideal for various SIP Wood Lathes