Sherline 37091 Chuck Adapters for Rotary Table Now you can attach a 1/4″ or 3/8″ drill chuck, an older Unimat chuck with 12 x 1 mm or 14 x 1 mm threads or a 1/2-20 Sears chuck to your Sherline rotary table. The adapter screws into the 3/8-16 threaded center hole of the table.