In message , CW
writes

The end of a pen turning mandrel is drilled with a standard center drill for
use with a 60 degree center in your lathe.


That would make sense as the standard revolving centre that comes with
Jet and other smaller lathes is nearer 30 degrees so they bottom out.
Would be nice if they had instructions with the kits we get. Even at a
demo at the shop recently they encountered the same issue so obviously
staff didn't know either

--
John