Ken, like to see what you come up with.

Jeff -- laid it out for the taper -- the slope is 1:3  -- that is it narrows 1/8th inch on each side for a 3/8 inch depth.   That was my best memory of configuation going from 1/2 inch opening at the outside to 1/4 across at the bottom.    The angles are 18 1/2 degrees and complementary 71 1/2 degrees -

Seems about right as the normal lace turning blanks were 5/16 to 3/8 inch with some bone blanks closer to 1/4 inch.


And then I in the shop with a 3/4 inch 1/2 inch socket in hand -- and put in into the O'Donnell chuck and it was an almost perfect fit.   I tried several other 1/2 inch sockets and they were fitting.    Few on this side of the pond have O'Donnell jaws, and because they have a ledge that catches the bottom of the socket, they are almost perfect.

Tried pin jaws  -- and they worked pretty good too --

I may have been solving the wrong problem -- and  just need to use 12 point  1/2 inch drive sockets.    And do not need fancy ones -- they will never wear out on a wood lathe.

I well understand the months -- and how they can drag on beyond estimates.   Especially the last 10% of the project.

Travel safely --  There are cars and trucks out to get you!!

Been know to ride on occasion -- but tis cold and wet here which discourages such.