The Rotur Deluxe Woodturning Compression Pen Mandrel holds pen blanks on the lathe in compression between the lathe headstock and tailstock, instead of the more traditional but less satisfactory way of screwing a nut up against the bushings and supporting the mandrel shaft with a live centre. The compression method means there is no tension on the mandrel shaft itself and therefore the pen mandrel is not prone to distortion or vibration, either of which can lead to "out of round" pens.

The mandrel shaft is held in a collet, which fits into the lathe headstock spindle by means of a morse taper arbor. At the other end is a hollow mandrel saver or support shaft, which fits into the lathe tailstock quill, also by means of a morse taper arbor.

Once the pen blanks and pen kit bushes are mounted on the shaft, the headstock is brought up so that any remaining length of shaft passes through the mandrel saver, which exerts a small amount of pressure on the end bush to hold everything in place. By bringing pressure to bear on the blanks and bushes, as opposed to tightening a nut against them on the mandrel shaft and pressing against the shaft with a live centre, the shaft remains free of tension and therefore does not distort.

Because the mandrel saver is completely hollow, there is no need to pack out the mandrel shaft with extra spacers, nor is there a need to reduce it's length at the headstock end, since any excess in length will be supported inside the mandrel saver. However, if you do wish to shorten its length for any reason, for instance if your tailstock quill is not hollow all the way though or if you're turning a particularly short work piece, it is easily achieved by loosening the collet and pushing the mandrel shaft further inside the arbor at the headstock.

The Rotur Deluxe Woodturning Compression Pen Mandrel does not benefit from the vast marketing machine that sells other makes, but none the less, in our opinion is quite possibly the best pen mandrel on the market. Unlike competing makes of compression pen mandrel, the Rotur mandrel shaft is held securely in place by a collet and not a grub screw. A collet will hold the mandrel shaft accurately and centrally, whereas a grub screw has no choice but to hold it fractionally off centre.

In addition, the Rotur mandrel shaft is 6.2mm in diameter, allowing for an accurate sliding fit on most commonly available pen kit bushes. (Beaufort Ink pen kit bushes are 6.25mm through the centre). There is no standard for pen mandrel shafts, and competing compression mandrels are sized at not much more than 6.1mm in diameter, which can lead to loose and rattling bushes.

There are no prizes for guessing the potential results of off centre mandrel shafts or loose bushes, which are no different to those of vibration or distortion. The Rotur Deluxe Woodturning Compression Pen Mandrel overcomes all these issues and makes turning a pen on a mandrel both accurate and easy.

This pen mandrel fits lathes with a 1 morse taper headstock spindle and tailstock quill