The Shopsmith 1/2 Inch Router Chuck turns your MARK into a great over-table router. This precision machined tool steel Router Chuck has been especially designed to slip onto your MARK V’s 5/8” Spindle and firmly grip any 1/2” shank Router Bit for over-table routing operations. Made specifically to handle the side thrust associated with Routing. This Router Chuck features two setscrews to grip your Router Bit firmly and a third setscrew to grip your MARK V’s spindle. CAUTION: Do NOT attempt to perform routing or similar side thrust operations with your 1/2” drill chuck, as this will damage your Chuck.