Key Bushing Cauls-sizing wrecked mortices

[Ric Brekne]

Hi there William

When I run into mortices that are wrecked its always been because 
someone has botched a rebushing job. Removal of old bushings seems to 
stump more then the occasional tech it would seem.  That being the case 
its just the surface area and perhaps 3-4 mm into the mortice that is 
ruined. Removing 5 mm is plenty in any case as new bushings shouldnt 
really be any more then 3 mm deep anyways.  Wood inserts to bring the 
surface area up to the origional height are easy enough to manufacture. 
Just need to be the width of your channel. Using the inside of the 
remaining mortice as a guide, glue them so they are flush, trim (sand) 
the sides of the keys as neccessary. Only tricky part is if you have a 
black key that is to thin on one side of the mortice to really glue a 
new piece into. You skip that side :) Yep I've done this.  Very similiar 
really to a routine described here a while back  for redoing balance pin 
holes.  

Cheers
RicB

Ric,

Have you done this?  Am I reading correctly that you would rout a channel,
glue in "shims", and then rout the final product to the proper dimension?
Or are you machining inserts that are properly sized?  I would think it
would be rather difficult to machine inserts, glue them in and come out with
a properly sized mortice, no?

I'd appreciate a clarification.

Respectfully,
William R. Monroe