Beall Collet Chucks are designed to hold small parts for turning very exactly, and without marring. Interchangeable collets get a tight grip on round tenon ended stock. Parts are turned with the tailstock end only, so turning can occur on both the sides and end of the turning without interference. Collets hold so well that hand tightening is usually sufficient for most work. Also useful for holding mandrels, small shop made face plates, metal turning blanks, and special jam chucks. Chuck and collets are precision ground to machinist tolerances. Size of collet refers to internal diameter before chucking. Chuck fits lathes using 1-1/4" x 8 tpi spindles. Complete Set - Includes chuck, five collet sizes (1/4", 3/8", 1/2", 5/8", and 3/4), and spanner.