Tear Down - Ladies Bulova Longchamp (Durowe 1980)

[Marc]

As promised in another post here is the little ladies Bulova Longchamp that I recently serviced. It's a 5.75''' x 6.75''' INT cal.1980 movement which according to Ranfft is also a Durowe 1980 or an AS 1977-5. 17 jewells and a 21600 train.

 

It's my sister-in-law's watch and it came to me because it kept stopping. On the Timegrapher things did not look good; averaging 6 minutes a day slow with a Max Delta of 6 minutes and 20 seconds between positions (yes - minutes!!), average amplitude of 140 degrees, and a beat error of about 4.0ms. About as bad as it gets and still running!!

 

 

Dial and hands off there doesn't seem to be anything damaged so hopefully this is just a COA and maybe a replacement mainspring.

 

 

Mainspring let down now I can start the strip down.

 

 

Balance, pallet fork, barrel bridge, and barrel now out. End and side shake on the train wheels is fine but the train is a bit sticky which does suggest gummy oil.

 

 

Train bridge off revealing the train wheels in all their glory.

 

 

The stripped out main plate, train side.

 

 

Dial side, set lever bridge removed showing the layout of the keyless works.

 

 

Main plate now fully stripped.

 

 

And balance reinstalled for cleaning minus jewels.

 

 

Every thing nice and shiny out of the cleaning machine. The mainspring looks absolutely fine; not set, and laying nice and flat on the bench with no distortion, so I will re-use it rather than replace. Notice the balance pivot jewels and end stones are different sizes. This is something that I always check when disassembling as the differences are not always as obvious as this and if you get the wrong ones in the wrong places it can cause all sorts of fun and games.

 

 

Mainspring in the winder ready to install.

 

 

Balance jewels oiled and reinstalled. This is when I check the free swinging of the balance and that the hairspring is sitting flat, with concentric coils, and not fouling anything. On movements that do not have adjustable stud carriers I also eyeball the impulse pin through the banking pins at this point and make any obvious adjustments to beat. I don't expect to get it spot on at this stage but it's nice to start off reasonably close, and you never know your luck. This one is adjustable though.

 

 

The train wheels back in.

 

 

Train bridge installed, barrel bridge reassembled and reinstalled. Everything spinning nice and free with some healthy recoil on just a couple of clicks of power on the ratchet wheel. Train pivots now oiled.

 

 

Pallet fork back in and checked for lock and draw before oiling the pallet stones. Balance reinstalled and starts running straight off. I love this moment, it gets me every time.

 

 

Keyless works back together and lubed.

 

 

And onto the Timegrapher for some tweaking. Not a bad result considering the starting point and nothing has been replaced.

 

 

Finally re-cased and ready to go home.

 

 

The resulting stats at full wind plus about 6 hours;

 

Position               Rate       Amplitude       Beat Error

Dial Up                +4s/d      282 degrees   0.0ms

Dial Down           +3s/d      270 degrees   0.0ms

Pendant Up        -13s/d     242 degrees   0.1ms

Pendant Down   +5s/d       227 degrees   0.2ms

Pendant Left      -19s/d      237 degrees  0.3ms

Pendant Right   -2s/d        248 degrees   0.3ms

 

Power reserve of >42 hours.

 

I could possibly get the rate and amplitude more consistent with a bit of hairspring tweaking but given the size of this little baby and the (very high in my case) risk of making things worse rather than better I have decided to leave well alone. I know my limitations and when to quit while the going is good. If it were my watch then I may have been tempted.

 

On the wrist (which is what actually matters) it is running close enough to spot on as to not be able to distinguish any error at all after a week of wear so I am happy with the end result.

 

Sorry about the somewhat dodgy point of focus on some of the pics, I hope that it doesn't detract too much. Will try harder next time :-)

 

 

 

[Marc]

I should point out  that my comments above regarding how the watch runs on the wrist should be considered in the context of the size of the dial and hands, and the lack of a seconds hand and minute indexes on the dial. It could actually be out by 15 to 20 seconds or more and not be noticeable.

:-)

[rustycolt]

Allow me to be the first to compliment a job very well done. An excellent project, Great result, and very well authored walkthrough. 

I applaud your methods and results. You are enjoying your hobby, and it shows  :thumbsu:

[Mark]

Fantastic pictures Marc, great post. Thanks :)

[Geo]

Excellent result and superb photos Marc, I really must stop being lazy taking hand held photos at 800ASA.

[bobm12]

Very well done Marc. Love the pictures, the thoroughness and the result! Real nice work!

 

Cheers,

 

Bob

[Marc]

Thanks for the comments folks.

 

I must endeavour to post a few more of these, I know how people like pictures ;-)