The Rotur Keyed Chuck & Mandrel set is a great way to utilize your lathe for drilling and boring operations.  Even small workpieces such as pen blanks can be drilled out centrally.  The mandrel has a 1/2″ 20tpi UNF thread which screws into the Rotur drill chuck. This means there is no risk of the chuck detaching from the mandrel body.  Chuck capacity 1.5mm to 13mm The Rotur Drill Chuck Mandrel is machined from high quality EN8M Steel. Available in 1MT and 2MT. Made in the UK by Planet Plus Ltd 2MT: DMC2