Messages: 217 Location: Bangkok, Thailand
Registered: November 2003
Another long term project completed...>
Mon, 01 October 2012 07:40
I have wanted a Valjoux 88 powered watch for a long time, but they always seemed to be out of reach for me. The Valjoux 88 was among the more complex movements that were in mass production up until the 1970's, superseded only in the late 90's by Valjoux 7751 triple date moonphase. Designed in the 1940's and built to the old Swiss standard of watchmaking, it's hard to find a nicer complicated movement than that. Only about 13,000 of these movements were made, not many for nearly 30 years of production of the Valjoux 72C on which it is based. A cheap one will cost around $3000, and although I know lots of people can afford that sort of money, I'm not one of them. So, quite a few years ago when a nice V88 dial showed up on ebay, I thought this could be the start of something new eventually!
Around 8 years further down the track, actually about 8 months ago, I was looking through my Valjoux parts boxes and realized I had a NOS V88 dial with no maker printed on it, a nice NOS V72C case made by Kelbert, and a few other odd V88 bits I had accumulated. And, I had a really good Valjoux 730 movement in a beaten up gold-filled case. There was more stuff there than I'd remembered. So, could I combine these parts into something useful? To cut a long story short, the answer was yes, and this is the result. A Valjoux 730 converted to a Valjoux 88 (or more like a Valjoux 886).
The first hurdle was to figure out what the difference is between a Valjoux 72C and a Valjoux 88. I have never worked on a real V88 in all my years of repairing, but am quite familiar with the 72C and 730. The main difference between a V72C and a V730 is that the V730 has a glucydur balance with flat hairspring beating at 21,600 bph (V72C is 18,000) and a Triovis micro regulator. They achieved this increase in beat rate simply by changing the 4th wheel from 60 teeth to 72 teeth, and changing the escape wheel pinion profile to suite the smaller teeth on the new 72 tooth 4th wheel. As for the difference between the V72C and V88, I was going to have to rely on parts lists and manuals to work it out. Searching the net was useless, no one seemed to know. But anyway, careful examination of the service manual indicated to me that the mainplate was actually the same as the V72C. The only difference I could see between the two calibres were 3 holes, one for the moonphase yoke stud, one for the moonphase yoke spring, and another for a dial support screw (and of course the V88 calibre stamp). Looking closely at the Valjoux 730 movement of mine, it was apparent that 2 of the 3 holes were present though not threaded, and the 3rd one was center marked but not drilled. I was quite surprised by that, as that meant that any V72C could be pulled aside on the production line and made into a V88, more or less by simply adding the necessary parts and changing a few others. I guess that kind of makes sense anyway. Those holes being present meant that the worst part was already taken care of - it would have been quite difficult to drill them exactly in the right place without a V88 movement to measure from. With that information I launched into hunting down the parts I needed. Launched being the operative word, followed by a slow crash and burn as I discovered how hard it is to find Valjoux 88 parts. What's more I also found out that most parts sellers don't know that a number of parts for the Valjoux 88 look the same as the V72C, but are in fact different in terms of height or other small details. So, I spent a fair bit of time hunting down parts, and getting lots of wrong ones. Once I had located the main V88 parts, I tapped the new holes in the mainplate, then hoped I could get the rest of the parts I needed. That being the various special screws, cannon pinion, hour wheel, hour runner, date star and hand set. Again, to cut a long story shorter, I was ultimately successful. This pic shows the movement trial-assembled in the case, with all the moonphase parts present.
This is a list of parts that had to be changed or added. Quite a lot of bits to simply make 1 wheel turn around! Refer to pic above:
1) Hour Hammer Cock 2) Moonphase Jumper 3) Moonphase Star
4) Hour Runner 5) Moonphase Yoke 6) Moonphase Yoke Spring
7) Moonphase Yoke Spring screw 8) Moonphase Corrector 9) Moonphase Yoke Stud
10) Date Corrector 11) Hour Recorder Bridge 12) 5 Special Screws as Dial Spacers
13) Cannon Pinion, Hour Wheel, Date Star
I only had one other problem to solve. Would a Valjoux 88 movement fit into my Valjoux 72C case? Here again, I was lucky. Sometimes, movements are located depth-wise and sideways by the dial, and then have a movement ring to hold the movement in a fixed vertical position. Other times, the movement "front-loads" into the case and is secured by case screws from behind. This is a choice made by the case designer, and with the first type, requires a dial of the correct diameter and thickness for everything to fit correctly. This usually means getting the stem hole in the movement to line up perfectly with the case tube. In this situation, the Kelbert case I had was a traditional front-loader, which meant that the dial diameter and thickness was slightly less critical because the movement position is determined by the lip on the pi;;ar plate. Unfortunately, the Valjoux 88 movement is 0.4mm higher than the V72C movement, the extra thickness due to the moophase parts. Way too much for it to fit. So, I had to machine out the bezel of the case to allow for the extra dial height. I couldn't increase the depth of the bezel, there wasn't enough material to do that, so what I had to do was machine out the opening of the ledge on which the crystal sits, such that the dial can pass up into the hole. Luckily, the dial I had was small enough to allow me to get away with that. Problem solved, the dial ends up just underneath the crystal and the edge of the crystal hides the 0.05mm gap around the edge of the dial nicely. And just to complete the pics of this watch, here's a movement shot. There aren't any changes to this side of it, but it looks pretty nice anyway, too good to ignore! Valjoux did such a great job on their earlier movements.
The most visible difference between a "real" Valjoux 88 and my conversion, at least when it is all cased up, are the day and month discs, which in my watch are slightly further below the dial than they should be. The parts I need to correct this just simply weren't available from any of my parts suppliers. I'm not surprised really, just amazed that I was able to get the main parts to make this work at all. Because those few parts weren't obtainable, I had to make a modification to the moonphase yoke (#5 above) to allow it to pick up the actuating pin on the day disc. If I can ever get those parts, the mod is quite reversible, so it's not a big problem.
All in all, I am very happy with the finished product, despite the fact that it may be a frankenwatch. It looks great and performs well too. With a NOS dial, hands and case, and a nice example of the movement all cleaned and serviced, it's the next best thing to a new watch, with the added pleasure of having done it myself.
- Rob B