All this good discussion on chisels has woken out of my slumber!  Two
things I would add:
    Fitting the taper to the socket becomes easier if you place a rod in
the socket that does not bottom out.  For example, a 1/4" rod in a socket
you know terminates at about 3/16".  Note the length of rod which is in
the socket and then take the diameter at the top.   When turning the
handle, mark the length, and then use calipers to turn the major and minor
diameters at their respective ends.  Connecting the two creates an *exact*
match of what is in the socket.  CAM?

     The Withebys and a good deal of the buck bros I have come in contact
with have been laminated.  Be sure and check they have not been worn past
the steel on those "stumps".

     And now a question for the masses....   Does anyone know of the heat
treat process used by these manufacturers?  Occurs to me that if they ran
a temper, an old chisel could well be into softer stuff.  Were they using
ovens??