Monday, 9 April 2012

Molnija 3602 balance repair

I'm writing this post in response to a reader's question that asked if I could give them some advice on how to correctly attach the balance spring and shaft on a Molnija 3602.

To start, if you're trying to restore a Molnija and you don't have the proper tools, then buying a parts movement on eBay is the easiest, cheapest and best way to get your watch back up and reliably running.

If you do need to re-attach a balance spring to the staff and you don't have the proper tools, you could use very fine pliers to re-crimp the spring collet. Depending on the quality of the balance spring collet (dented, rusted, etc) this may not be an option. There is NO guarantee that this method will work or that it will produce reliable results or that you'll have anything more than a paperweight when you're done. It is also the easiest way to damage a balance spring - which are sooo easy to mess up even when you're being super careful.

In principle, if you can drive the balance spring collet onto the balance staff, in perfect alignment, and maintain sufficient friction between the staff and the collet, then you can complete the repair. This is much easier said than done, and the proper tools make the world of difference.

The goal: to join these three items - the balance spring & collet, the balance staff, and the balance wheel. These items were kicking around my parts draw - you may notice that the balance wheel is a little deformed, after I took this first photo I used a flat punch against an anvil to flatten it out.


Closeups (as good as my camera can manage):


 As I mentioned in a previous post my staking set does not have a full compliment of anvils, so I've used the best anvil that I have at hand to drive the balance wheel and staff together prior to riveting.

Step 1: Driving the balance staff and balance wheel together. Align everything. Select the anvil carefully, I've used a flat faced punch to gently tap the two items together. I have to emphasise just how little force needs to be used, the balance wheel can very easily be ruined..

 

 Step 2: Riveting the staff to the wheel. A domed punch/stake can be used to peen over the lip on the staff which will then fix the wheel to the staff.

 

 Examine the quality of the work, checking the wheel for trueness, etc. (I'm not going to put this in a watch any time soon, so I haven't bothered perfecting the wheel's poise/trueness).


Step 3: Driving the balance spring collet to the balance staff. Again, alignment is critical, as well as the correct selection of the stake. If the collet on the inside of the balance spring is loose on the staff, a concave stake may be able to shrink it, but then this also may damage the inner edge of the spring. If you're feeling like a rebel (with the right tools), fine pliers might do the job. The collet should have a tight friction fit and not a rivet fixing onto the staff.


Job done! Fix it to the balance cock & see how it runs. Because Molnijas have a regulator stem, you've got a little margin to correct the orientation of the collet in relation to the staff. However, it is still always best to align the entire job (wheel, staff, spring), otherwise you may install the balance and find that it wants to sit 20 degrees from the lever and simply wont engage it.


Elgin Ladies Watch


 I found this gem on eBay a couple of months ago, ADU35 in total (inc shipping). I'm really quite surprised by the quality and low cost of ladies watches (I must be the only person shopping for them..). This particular Elgin has a 10k GP case and works perfectly (after cleaning):

.. I'm still trying to track down what Elgin movement this is, so if you know the caliber number feel free to post it in the comments section.


 This may be the smallest movement I've worked on, the next photo will show the relative size of the watch to my club-like thumb, with the stamped 10k case back:

 

 Once the watch is opened up, the low cost is even more surprising. The movement has 15 jewels and is adjusted to 4 positions. All the jewels are set in nickel?? chatons, which suggest that this movement is designed for a long life.


 The tear down:


 The click, anchor and screws are all black-polished and the click spring and yoke spring are blued - something which cannot be seen with my low quality camera - again, very surprising for a cheap watch (which is now obviously seen as under priced).

 Overall, a superbly designed and finished movement.

Luch 2209 manual wind

This is my second favorite Soviet wristwatch movement of the ubiquitous Pobeda.The Luch 2209 has some interesting and arguably pointless design features, but overall, it's accurate & tough. Before I start:


To start the assembly, I've got the mainplate with the set lever/screw and shock spring installed:


The first unusual aspect of the movement is the incredibly small centre wheel and cannon pinion. These are truly tiny pieces..

 

The keyless works is mostly conventional in its design, except for the set wheels. Most comparable mechanical movements would have just one set wheel, however, this Luch has two. The wheels are the same size, so there is no change in the ratio of input/output, and the physical distance between the clutch and the minute wheel do not seem to warrant the extra wheel (I think it could be achieved with one wheel):


With the bridge installed:


Now for the reverse:


The preference of the Luch 2209's designer for adding superfluous wheels is again demonstrated on the barrel bridge. I think that the ratchet/winding wheel could have been bigger (as it is on most wristwatch movements of this size), and the set of transmission wheels could then subsequently be reduced in number with a slightly larger remaining wheel.

 

Hidden under the going train bridge, is a smaller bridge that holds two small gears. The only other watch I've seen a similar setup in was Slava from 60's..


The reason for have this small intermediate bridge is to internalize the seconds gearing. In most other watches, the seconds wheel would sit on top of the center wheel and may require another bridge which would also make the movement thicker. This design feature, when coupled with the very small center wheel that I pointed out at the start of the assembly, contribute to a very compact design.


This particular movement belongs in a nice square 10k GP case, so the movement holder is simply a square of aluminum.


 These movements are less common that the Pobeda, but definitely more fun to assemble. They are generally a little cheaper than the Pobeda and just look like a quality movement.