Job Number 210153, Hampden Special

This Hampden cleaned up really well. It's the movement from the previous post, here, an 18 size Hampden Special, 17 jewels, made about 1896.

On the dial side there were two broken springs related to the lever. One of these holds the lever itself in snugly when it is in winding position. The other acts to push the mechanism into the "default" winding mode when the lever is in. Pulling the lever out pushes against that spring to enable setting. Both these were broken, and the broken pieces where nowhere to be found.

This creates a bit of a mystery. How to replace these springs when what was there before is unknown? The best approach in this situation is to carefully study the mechanism and understand how the springs do their respective jobs given the screws and posts that define their endpoints. 

It helps that I have seen this type of arrangement many times before, but just the same, using springs I have, and not make new ones from scratch, requires careful study of the dimensions and geometry.

For my first attempt, I found a spring that fit will between the corner of the vibrating arm and the fixed point on the plate. The spring's maximum compression is thus in the middle of the lever's travel in and out. The lever thus gets a good feel to it. 

However, there's no tension pushing the vibrating arm to winding mode when the lever isn't pushing on it. Just the same, this probably would work since the gear motion when winding tends to "roll" the arm toward the ratchet wheel anyway. Indeed, many movements, including smaller Elgins (which drive me crazy for exactly this reason) depend on this tendency to engage winding.

I kept looking at springs for a better solution.

For the final configuration I used two springs. The one acting on the lever is again most relaxed at the two lever positions, so the lever has a good feel and tend to stay in or out.

The other spring pulls the vibrating arm into winding mode when the lever in in, and not pushing on it.

This is setting mode, the next photo is winding mode.

As an aside, the spring acting on the lever isn't really right. It would have been a spring with coils proving slightly less tension, but being itself under less stress while also staying out of the way of the minute wheel. Other Hampdens have such an arrangement.

The album for this project is here:
https://photos.app.goo.gl/2NgeUAoC7LyX8FV98

Mainsprings for this watch are scarce. I obtained an Illinois spring with very close specs. It will work fine.

 

Hampdens always seem to me to have a lot of parts. Here's the ratchet wheel and click. This all get covered with a clamp that also has a notch guiding the vibrating arm.

It seems to be running pretty well. How about that regulator! 

Note the Hamilton style clamp on the hairspring stud. Those are always fun.

The movement has a broken cannon pinion (broken one upper right). I found two candidate replacements. One was much too loose. Luckily the other was much more snug. I say luckily because this type of cannon pinion is almost impossible to tighten. You pretty much have to find one that fits as is. They vary a lot though. Q/A at the time wasn't really a thing.

Oddball dust cover... The brass strip is held to an otherwise free part, that fits over the mainspring barrel, with two screws.

Not sure how testing will go on this one. But it may just have to be as it is. Parts are just not common.

Find more Hampden examples here:

https://elgintime.blogspot.com/search/label/Hampden