I obtained this 1920’s Bulova watch in a hinge-back case about half a year ago. It was running about 6 minutes fast per day, making it a good candidate for a servicing. This is a small watch, but is not out of the ordinary for a man’s timepiece from this era, when watch sizes overall were much smaller than today. The case measures only 35.5mm lug to lug, 30.5mm across the dial, and is 11mm thick. The case is base metal with embossed patterns on the bezel and sides. The dial has been re-finished to the extent of having what used to be luminous numerals re-painted in black (not the best job I’ve ever seen), and the luminous material in the hands had
The case has a hinged back that opens around 75 degrees to expose the movement. A thin yellow-tinted piece of celluloid serves as a clear protective cover over the movement, held in place by a snap-on metal retainer ring. Within is the highlight of this watch, the movement. This is a Bulova 10AN 15 jewel manual-wind, a really nice, quality movement. It is actually an FHF 3 (Fontainmelon) in disguise – a 10 1/2 ligne 18,000 bph movement. Stamped inside the hinged back is the following:
Pat. Jan 11, 1927
I was quite impressed with finding such a quality movement in a base metal watch that probably wasn’t overly expensive in its day. Some indication of the quality of this little movement is found in the use of a Breguet
over coil hairspring, a cut bi-metallic screwed balance, perlage on all inside plates, bridges and cocks anglaged and mirror polished, anglaged and polished fork and pallets, polished steel escape wheel, and polished keyless work parts. I took a good close look at the movement under a 10x microscope, and apart from the ravages of time and previous watchmakers, the finishing, both functional and decorative, was very well done.
For a close look at the very well made lever from an FHF 3, have a look at Rob B’s TZ Classics post,
“A Jewel among Watch Levers”.
I worked on the movement in conjunction with fellow TimeZoner, Rob B. The movement held no great surprises in disassembly, and so I won’t dwell on that. Here is the movement partially disassembled , with the balance, and mainspring barrel/bridge assemblies removed. There was a very good reason for taking a good close look at both.
The movement was quite dirty, and had strange fibrous material, for all the world like miniature spider’s web, on all the plates and cocks (no spiders could be found!) This was really only visible under the 10x microscope, and was removed by normal ultrasonic cleaning. It was noted that the balance amplitude appeared quite low, and it would be interesting to see how that was affected by the cleaning.
Below is a pic of the dial-side of the bottom plate, showing the perlaged finish:
Another problem that became evident was that the stem was incorrect for the movement, and was much too loose. A new correct stem was found and trimmed to length, but the thread on this did not match the old crown (which appeared to be a generic one). The new stem is shown in the pic above. For the time being the watch is sporting a Bulova Accutron crown, until a suitable one can be obtained to fit the new stem.
Upon reassembly of the cleaned movement, the balance still displayed low amplitude of around 180 degrees. A new mainspring was needed, and so the old one was taken out and measurements taken. A trip to the local
watch parts supplier unearthed the new mainspring shown below. This was listed as being for a Cyma 459, but was of suitable dimensions for the FHF 3 in the
Shown here are the open barrel and the new mainspring housed in its retaining washer. Care must be taken to ensure the mainspring is inserted in the correct direction, as you only get one shot at it!
The new mainspring is inserted into the barrel by laying it on top and pressing firmly down. The mainspring is pushed out of its retaining washer and into the barrel. The mainspring arbor is then inserted and the eye on the end of the mainspring is nudged until it engages the hook on the arbor.
The new mainspring bought the old thing back to life with a much more healthy balance amplitude of around 270 degrees. Yet another problem had been fixed.
Now that a decent balance amplitude had been obtained, timing of the movement could be undertaken. The watch continued to run very fast, and Rob and I checked all possible causes. The hairspring sticking problem had been fixed, the new mainspring appeared to be suitable, the balance was in poise, and the index pins set correctly. It did appear that at some time in its life, this movement may have had either the hairspring and/or balance replaced. This may have been the reason for the watch running fast in the first place, and may well have destined it to have been set aside as a bad timekeeper, until it eventually found its way into my possession.
So, the watch had another problem, but Rob had an answer to this one too. It was decided to add timing washers to the balance to slow it down. Here is a pic of a selection of timing washers:
These washers are extremely small, and are used in pairs to alter the weight of the balance whilst still maintaining poise. They are positioned under the heads of the screws located in the neutral position of the balance arms – one of the timing washers can be seen in this close-up pic, as can the bi-metallic construction of the balance, and the cut:
Being fiddly little critters, there is a special tool for handling them, called appropriately enough, a Balance Screw Holder (never would have guessed that one!). Here’s a pic of the tool used in this delicate operation:
The crystal found in the watch was slightly undersize, and the glue used to secure it had failed, allowing the crystal to become loose. Rather than re-glue the undersized crystal it was decided to obtain a new one of the correct size, and also one with a lesser dome height which would be more in keeping with the style of the watch. Again, a suitable replacement acrylic crystal was obtained from the
watch parts supplier, as shown below, and fitted to the watch, resulting in a lower profile and less visual distortion of the numerals on the dial.
The hands also needed attention, as the old discoloured luminous material was unsightly. For a description of the method used to clean and reapply luminous material to these hands, please have a look at my TZ Classics post,
“Restoring Luminous Watch Hands”.
So, this little Bulova proved to have its fair share of problems, but sometimes you get that. You can never really know just what has happened to a watch in all of those intervening years. Luckily, very few problems are beyond being rectified, and the quality of such a watch makes it all worthwhile. I found the experience gained in resolving the problems to be very beneficial.
Here is the watch ticking away in good health after all the work – once again it is a reliable timekeeper.