Perpetually Ludwig – Inside the Ulysse Nardin GMT Perpetual

Part 2

text and images by A Watchmaker, edited by Hans Zbinden

Here is the program wheel completely disassembled with all of it’s satellite wheels removed for your scrutiny.

Wheel number one advances the decade wheel of the date one number for each of it’s four teeth. The reason for the uneven spacing is 10 days from 1st to 10th, 11th to 20th, and 21st to 30th. But only 2 days from 30th to 31st and then back to the 1st again. So as one can see, the program wheel makes one complete revolution per month.

Wheel number two is the February 28th wheel. Looking carefully at it one will see that it only has three large teeth. That allows for leap year programming so that in leap years it will show February 29th. The wheels on its left, together with the single tooth seen under wheel three, are its driving wheels.

Wheel number three has five long teeth for the five months which have less than 31 days. February, April, June, September and November.

Wheel number four has one long tooth for February 29th. Wheels number three and four make one revolution per year.

Wheel number five is the date wheel. Its 31 teeth accomplish the changing of the date.

The 31 tooth brass wheel under wheel number two is the actual driving wheel that drives the complete program wheel assembly.

Now we get to put it all together as a complete unit.

This close-up shows the longer teeth in position to effect the jump from February 28th and February 30th, or any month that doesn’t have 31 days. What about the tooth for February 29th? That wheel fits on top and is in the next photo.

Here one can see all the wheels in position ready to effect the jump from February 28th to March 1st.

The 24 hour wheel has four long teeth which engage the program wheel in order to flip the date either one, two, three or four days, depending on the month. Tooth #1 engages the green arrowed tooth. Tooth #2 engages the blue arrowed tooth. Tooth #3 engages the red arrowed tooth, and tooth number four always engages the brass driving wheel once a day to effect the date change, including from the 31st to the 1st.

The overall view before the last of the program wheel, the date wheel, is fitted.

Before the top plate for that section is fitted.

Voila!! All completely assembled ready for the fitting of the indicator discs.

A close-up of the holes to help the watchmaker with programming it correctly. This shows the month wheel set for March. The other wheels have the holes set for February 28th so that the watchmaker can set them correctly, and then check that it does indeed jump from the 28th to the 1st.

All the wheels in place and ready for the dial and hands to be fitted. Note that the programming is not correct as this photo was taken while I was disassembling the watch, prior to servicing.

A few thoughts on this unique movement.

While not particularly watchmaker friendly as far as servicing goes – and no, I won’t tell you how long it took me to figure out exactly how the calendar works and to program it correctly – it is extremely user friendly. Unlike most perpetual calendars, one can easily adjust the date either forwards or backwards. In the jet age, this is especially useful for those of you who do a lot of traveling.

While Ulysse Nardin do use the Lemania as a base movement, just the going train and automatic parts have not been modified, save for the enamel inlaid platinum weight. Due to the barrel originally having to accommodate the hour recorder from the original chronograph, virtually everything else on the dial side has been modified. Some modifications are only slight and others involve a lot more work. The watch that I serviced tested out as very accurate and needed no adjustments on my part. I think that they have done an excellent job in both its design and execution.

The fit and finish of the working parts, while not up to Patek Philippe’s peerless standards, is still excellent none the less. There is extremely little backlash in the engaging of the teeth due both to their very special shapes and the extreme accuracy of their cut. This is further helped by the teeth resting flat up against the round section of the various wheels to limit backlash even further.

The only disappointing thing for me was the non-existent aesthetic finishing on the non-visible parts of the various plates. This is easily seen in the accompanying photos. Of course this doesn’t affect the functioning of the watch in any way whatsoever, but still at this price point I would have liked it to be a little bit better. Obviously if they did it up to Patek Philippe’s standards, it would also have to have their high price too. Just a minor complaint on my part, and something that I feel can probably be taken care of with only a small increase in price, if any.

All in all, from this watchmakers point of view, I think that Ulysse Nardin have done an outstanding job and produced an entirely original and unique watch. No easy feat in this day and age. And they’ve made it reasonably affordable too. I think that it represents excellent value for the money.

Ulysse Nardin’s Technical Director comments on the article

Congratulations! You disassembled and reassembled this fascinating caliber with high professionalism. The only remark I would have is about the Lemania base caliber. I was not at UN in the days when this project was developed, maybe Mr.Schnyder can confirm the true story. As you mentioned, the old Omega caliber has been chosen by the former development team of Ebel, jointly with UN as a sound caliber to be used by the 2 firms, Ebel for its Chronograph (competition to El Primero) and UN for our Perpetual calendar. The construction has been redone from scratch, using all possible well functioning parts of the original caliber, as you mentioned. Lemania in these time was the New Lemania, independent company earlier “abandonned” by Omega. That is only after the construction by Ebel/UN that the production of the ebauche was confided to Lemania. We did not choose an existing Lemania product as base caliber for our Perpetual.

Thank you for your good job explaining the genius of Ludwig’s solutions for the program-wheel!

Best regards

Pierre Gygax

Click here to return to Part 1