Elgin Grade 455

This watch is an Elgin grade 455, 16 size, 19 jewels, made about 1920.

The later higher end models, in nickle finish, usually had a elaborate decorative work. Most of the base plate, seen here, is never visible except to the watchmaker.

Replacing a broken balance staff starts by cutting away the back hub of the old staff, to remove it from the balance wheel/

 Here it is almost entirely cut away.

The new staff is riveted to the balance wheel, using the staking tool.

First a round headed, hollow, punch is used to spread the rivet. A flat headed, hollow, punch is used to finish the job neatly.

Installed the roller table, with the roller jewel, takes a special punch with a notch for the jewel.

This movement has a two-piece double roller. After the first part, with the jewel, is pressed in place, and second part is friction fit on above it.

Next is the hairspring.

The hairspring presses on the assembly, on the opposite side from the rollers, friction fit.

It's position is important. The stud at the outer end of the spring is held by the balance cock, which also has the upper balance jewel in which the balance wheel turns. The spring has to be turned on the staff so that the stud falls such that when at rest, in the middle of its to and fro motion, the roller jewel falls exactly midway in the middle of the pallet fork (on a line joining the balance jewel and the pallet fork jewel).

This is so the balance wheel will rotate an equal amount to the left and to the right as the watch runs. If this set up is not correct, the watch is said to be "out of beat". If it's off enough, the irregularity in the "tick-tick" cycle is audible even to the untrained ear. The balance turning too far one way or the other wastes power, causes unstable time keeping, and can stop the watch.

The roller table and hairspring in place, completes the balance assembly, or "balance complete" as the component is sometimes called.

This watch has an old dial repair that seems to be, my guess would be, epoxy. I've gone over it again to improve it some.