Cannon Pinion Fit

The outer diameter of this replacement cannon pinion, which took a while to find, has to be reduced a bit. Here it is friction fit on a piece of scrap. Frequent trial fit to the hour wheel is required. If you take off too much, you can't put it back... After the fit is nearly right, the surface is polished to a nice shine. 

It is often the case with replacement parts that they aren't exactly right, particularly the older ones, even when they are supposed to be "the right part". Even during the original assembly at the factory, parts were hand-fit. And it's one the rules of this sort of work that we never modify other parts to find the replacement, always alter the replacement.

When you open up an old watch, you'll find 100 years worth of repairs of all sorts and all sorts of parts, often hand made from scratch. I am sometimes asked by potential customers if I use only factory original parts. It's hard to explain the many reasons that this question doesn't even make sense, not the least of which is that the factories that made these parts have not existed for decades or longer.

Elgin Grade 7

Here's another Google+ Auto-Awesome image of an 18 size, 7 jewel Elgin pocketwatch movement, Grade 7.

This is a key-wind, key-set movement, and a very early design.

Elgin Grade 7

Here's some details of the ratchet mechanism on an 18 size Elgin watch.  This is their very early key wind design.  The hole in the lower part of the cover allows the watchmaker to reach in and release the ratchet to let down the spring for service.

Ad-Hoc Parts

Antique watches have very long histories of ad-hoc repairs. On this one it seems a proper case screw, or case screw washer was apparently not to be had. Someone has used an old star wheel an a plate screw to hold the movement in the case.

I was once asked if I use only factory new parts in watches. This question is off base in a couple of ways. One is that parts for these watches have not been manufactured for 100 years or more. There is no one you can just call up to order something or other. Secondly, parts were often not made in a factory to begin with. I see quite a lot of hand-made parts in watches. Even for machine made watches like Elgins, in the 18th century in particular it was much more cost effective to make a part than to have a "real" one shipped from the factory.

Elgin Grade 207

This Google Auto-Awesome image is a grade 207 lever-set Elgin pocketwatch, 18 size with 7 jewels

This one was made about 1903.

Assembling the Balance Assembly

The balance wheel is riveted onto a new staff using the staking set, first with a rounded hollow punch to spread the rivet, then a flat hollow punch to finish it.

Then the roller table is re installed, followed by the hairspring.

Removing a Broken Balance Staff

To install a new staff, the the shoulder is cut very nearly off the old one on the lathe.  Then it is popped off the balance using the staking set.

The result is a little washer - the last bit of the cut down shoulder.