What is this for?

[JRobCards]

When I first bought a starter kit for pen turning, it came with a standard mandrel with 7mm bushings and this nut and rubber piece. I am still trying to figure out what they are for. It has always plagued my mind because even my woodwork teacher at school (who wanted me to be the guinea pig for pen turning to see how easy it would be for someone to learn how to) does not know....

Any help?

 

[JasonC]

Explanation here: Buy 2 MT Mandrel at Woodcraft.com

 

[nativewooder]

It's what we here in the States refer to as a compression fitting.

 

[its_virgil]

The compression fitting takes the place of the brass nut for turning short single barrel items. I never found it to be satisfactory so I just used several 7mm bushings as spacers. Then I found the adjustable mandrels.
Do a good turn daily!
Don

 

[KBs Pensnmore]

Ah-ha, so you don't have to fill the mandrel with spacers.
Thanks for that, now I know.
Kryn