This series shows the steps
for making a new mainspring barrel for an English pocket
chronometer. This watch had a number modifications. In fact,
the repairs to the barrel cap are a separate article. The barrel
wall had been sleeved in an apparent effort to increase the barrel
height to accommodate mainspring the "watchmaker" happened to
have at hand. This lead to two problems. First, the
increased wall thickness interfered with mating pinion. Second,
the inreased height meant the stop work fouled the underside of the
bridge (which led to removal of the stopworks and modification of the
is a good example of the value of a large lathe and why I use my 8 inch
lathe extensively for watches. First the material has to prepared.
turned a "spigot" on the end of the barrel blank while it was
on the Habegger to facilitate holding the work throughout the
process. Below I am turning the blank to size on the 10mm lathe
which will also serve as my index head when cutting the teeth.
the teeth on the horizontal mill.
teeth cut and spigot removed. Next to it is the original barrel
after I had tried to remove the added wall. It was then that I
decided that a new barrel was needed.
the recess for the mainspring.
barrel with repaired cap next to original but modified barrel.
barrel in place.