I was debating something like a circle of wood bigger than the cole jaws
that I could screw to the cole jaws with the correct machine screws and
then construct rubber stoppers that could be put screwed into the wood
either with bolts going all the way through. If I cut the circle into
quarters this would extend the range of the cole jaws.

However I bet I would not even need a complete circle and maybe
rectangulare pieces might work.

PS I don't have a swing problem because my lathe has a rotating headstock.

Derek Andrews wrote:

william kossack wrote:

I normally reverse a bowl onto my cole jaws and turn the bottom
removing the tenon or anything else as I put the last finishing
touches on the underside.
This bowl is just slightly too big for the cole jaws I have but I
have others that are roughed out and drying that are coming down up
soon.


I have made several sets of extension arms for my Nova Cole jaws. Each
set comprises 8 L-shaped wooden arms. The long side of each arm has
two holes to bolt to the cole jaws, and a block of wood is glued to
the end of each arm. The cole jaws are closed right up, and the inside
edge of the blocks are faced off so they run true and have a slight
dovetail grip. This approach is also useful for bowls that don't have
a rim suitable to grip. The first set I made was to hold these small
bowls:
http://www.seafoamwoodturning.com/Shopping/BB_bowl.htm


Obviously you need sufficient swing on the lathe to spin this
helicopter-like contraption, and there are safety considerations with
this approach. Don't run it too fast. I have VS so I can start at 0rpm
and work up - I'm not sure I would recommend this on a non VS lathe.
You also need to be very aware of where the extensions are, and if you
have any doubts about the construction, especially the glue up, don't
use it.

Another option is to build a donut chuck, but I assume you really
wanted to make use of what you already have.