Can you engage the balance wheel lock on a Hamilton Model 21 Chronometer while the clock is running, or, should you wait until the clock runs down?
There was a recent thread on the Chronometer forum which discussed locking of the model 21 balance wheel. If you check out that thread, you will notice that there was a balance wheel LOCK, and a balance wheel BRAKE. The LOCK (as shown in the thread) could not be applied with the chronometer running, period. The BRAKE (as shown in the thread) could be safely applied with the chronometer running. That thread shows a brake, and a lock. It depends on what you are referring to as a lock, as to whether the balance wheel would need to be stopped. https://mb.nawcc.org/showthread.php?132931-Unexplained-Holes-in-Hamilton-s-Model-21-Lower-Plate I have added a link to that thread.
