The advantages of this pen mandrel design are that spacers are no longer necessary to make up the difference between the length of the pen blanks and the mandrel. This also helps to eliminate any vibration encountered when turning blanks on a longer than necessary mandrel shaft. The length of the shaft is adjustable and can be shortened or extended by loosening the locknut at the headstock end. By simply removing the shaft, you also have a really compact and versatile collet chuck which is extremely useful for holding small components for turning. Additional ER20 collets ranging in size from 2-13mm are available.