I'd just like to dive in here.  There are circumstances where
professional pinners will replace a small group of pins, such as
a winding key being dropped onto an otherwise 'perfect' cylinder.

There is cement in the cylinder but it softens at about 80 degrees
Celsius.

1. Carefully warm the cylinder around the pin.  You should take your
time and let it fully warm but, please, do not go over 80 C., as you
risk the wax pulling away from the cylinder wall.

2. Use a fine taper punch with the tip filed flat to tap the pin
into the cylinder.  The tip of the pin should be no more than 0.012"
diameter.  Be careful, you don't want to mark the cylinder.

3. Push the pin in with a hollow punch; finished length should be
just more than the other pins.

4. File the end of the pin flat; it's best to use a diamond file and
don't overdo it -- you're not trying to reach the finished height at
this stage.

5. Make sure that the cylinder is still warm and _very_ carefully use a
flat piece of steel (the side of a lathe tool is good for this) to push
the pin down to the same height as the surrounding pins.  The warm area
should not be wider than the length of steel used.

The job is a real pita; it's really only worthwhile on a good quality
cylinder with very small local damage.  Advantage: the new pin matches
the existing pins so there's no need to reposition the comb.

The above technique is for straight pins.  Depending on the angle,
raked pins should be finished very slightly higher, maybe 0.001" or so,
then bent forwards.  Again, you can check with a flat piece of steel.

Good luck,

Jim Weir
Kirriemuir, Angus, Scotland
combwork@aol.com.geentroep [delete ".geentroep" to reply]