Adapt your Insert Type NOVA chuck to a 1 1/8″ 12TPI RH UNF lathe. Allows you to keep the same chuck and accessories if you change your lathe. You only need to change the insert/adpater. The internal thread is 1 1/8″ 12TPI RH and the external thread matches the NOVA insert type chucks to simply and easily screw into the back of your NOVA Insert Type Chuck. Now your NOVA insert type chuck is ready to attach to your 1 1/8″ 12TPI RH threaded lathe spindle. Safety Advisory! Only use authentic NOVA accessories on your NOVA chuck. Using non genuine NOVA and copies of accessories could lead to operation and safety issues and will void our market leading warranty. NOVA accessories are designed for use only on NOVA Chucks. Do not use on any other chuck.