1942 Bulova One-Button Chronograph Caliber 10AH

When it comes to chronographs, I am unable to think of a single personal instance in which I have needed the function for more than one minute. Clearly the chronograph is not the most useful of complications, but that does not temper my (or the world’s) fascination with them. Until very recently the invention of the chronograph was attributed to Nicolas Rieussec. It was presented to King Louis XVIII in 1821 as a way to time how long the horse races lasted. This year credit was called into question when ancestors of Louis Moinet presented an extraordinary chronograph that is believed to be from 1816. It is definitely a piece worth looking up.

This Bulova One-Button has been on my restore wish list forever. Recently I was lucky enough to snag two of them and this was the first one I got to restore.

This incredibly rare 1942 “One-Button” is a wonderful and elegantly understated chronograph distinguished by its unusual button found on the crown. One can easily pass by this watch thinking it to be time only, but a second glance reveals both a sub-dial second hand and a sweep-second hand. The latter is a sixty-second register controlled by the chronograph gears. It includes a start/stop/reset function all engaged by pressing the button protruding from the crown. This is one of the smallest mechanical production chronographs ever made, and certainly one of the more rare Bulova pieces.

Bulova made this 10AH movement by taking a standard movement and modifying it to add the one-minute recorder. This method of fabrication is both a blessing and a curse when it comes to restoration. If something is wrong with the main works then it is very easy to find replacement parts, but if something is wrong with any of the unique chronograph parts it is near impossible to find replacements (this particular watch had a combination of both.)

I got this watch with a cloudy scratched crystal and in non-running condition. I was incredibly pleased to find that underneath the crystal the dial was in amazing original condition and had not been refinished. A great way to roughly determine a redial is to look very closely at the small numerals. Re-dialers can do amazing things, but even the best ones are often unable to perfectly replicate the fine details of the smallest numbers such as their specific shapes or alignment. This is just one reason that re-dials just never look the same. Look at the two pictures below for a great recent example. The picture on the left is the original dial and the one on the right has been redialed. You will see a world of difference, and a major reason that the refinished watch just sold for considerably less than a full original should.

Bulova 10AH original dial Bulova 10AH Redial

After disassembly I found two major problems: a horribly disfigured hairspring and broken teeth on the cannon pinion (the piece that carries the minute hand.) The first problem was easily solved by going into my parts stock and digging up a “harvester movement” with an interchangeable balance complete. The second problem required a special and discontinued part that I could only find in the UK.

With all the new parts installed, a case polishing, and a new crystal this over 70 year-old watch is back up and running beautifully. It’s always incredibly satisfying to put the balance in and see a watch come to life but it is even more exhilarating to push a button from 1942 and watch a chronograph spring into action.

Bulova 10AH Feature Bulova 10AH Crown Bulova 10AH Movement Bulova 10AH Side

Vintage Heuer Monaco Valjoux Caliber 7736 Chronograph

There are some movements that are made to last forever. Unfortunately, they are sometimes built along with Gaskets that were not. This iconic Heuer Monaco required the most labor I have ever put into a watch before even getting to the movement

Made famous by Steve McQueen, the Heuer Monaco became one of the most iconic, and easily the most recognizable chronographs ever made. In addition to its rarity and collectability, it also has a design flaw that has come to haunt it and its devoted collector base. Heuer decided to have this incredibly robust case clamp together with a gasket positioned adjacent to the crystal and dial (see picture below.) Old gaskets on many watches suffer melt (Bulovas, Zodiacs, Omegas, you name it, I’ve opened it and gotten melted rubber on my hands) but these gaskets are usually on the back, making it an easy clean up and never posing a threat to the delicate dial and hands. On the Monaco however, gasket melt poses no threat to the movement, but can and in many cases does ruin the dial (and the value.)

This watch had never been opened in its life. Upon close inspection I saw a thin black line on the edge of the crystal that indicated the notorious problem with these watches was indeed a reality. The gasket had melted. It is an incredibly sad thing to see such a stupid problem have such a rough impact on a piece such as this. Worse than the gooey mess that the melt leaves behind, the melted rubber is ever so slightly acidic, and so its contact with the dial can eat away at the finish and the metal. Incredibly the damage was minor given that this watch had been sitting in a box for 20 years. After carefully removing the melted rubber from the dial, the case was much easier to get to. A run through the ultrasonic cleaner and it was as good as new.


Heuer Monaco Gasket Melt Heuer Monaco Melt Clean-up Heuer Monaco Dirty Case


Heuer Monaco Clean Dial Heuer Monaco Clean CaseHeuer Monaco Clean

Once done with the annoying, messy, and time-consuming task of the gasket clean up, I finally got to the movement. From the second I received this watch I knew that the movement was perfect. Valjouxs are easily the most reliable mass-used vintage chronograph movement. This Caliber 7736 was no exception. A full wind and a ride on the Timegrapher (a machine, or actually a fancy microphone, to check the time-keeping accuracy) indicated that this piece was maintained with care and was in pristine, like-new condition. The gasket melt, although treacherous on the dial, must have helped to form a hermetic seal that prevented even a speck of dust from getting in to the movement.


Sometimes you take apart a movement to try and figure out what is wrong (repair), and sometimes (as in this case) you just try to not mess anything up but make sure its good to run for another couple years (maintain.)

I gave this a disassembly, cleaning, and oiling, and put it on the timegrapher again to make sure I didn’t screw anything up. Sure enough it ran just as well as before. After adding a new modern gasket, a new crystal, and a new band I could give my friend the assurance that his father’s watch was like new again. Although some of the dollar value had been hit by the melt of the gasket, the sentimental value of the piece was preserved.

Heuer Monaco Complete