I have a constellation that was serviced this past august that on the top position it is consistently running at +/- 2 seconds, with zero beat errors, but the amplitude seems rather low at around 240. Is that the normal range for this caliber? The lift angle is set to 49. I'm just curious, trying to learn.

 

240 sounds within a safe range to me. Can't speak about the correct lift angle though.

 

Having learned this craft over a period beginning before most of you were born, and having relied on an ancient Vibrograph B200 over the last 40 years, we relied on visual perception to judge amplitude. I am assuming the 240 degrees refers to how far the balance turns from neutral to one extreme? Times 2, that would be 480 degrees? If I am correct, there's nothing wrong with that amplitude. Especially considering the accuracy.

 

I just got a timegrapher so I'm having fun figuring out what the readings mean. It reminds me of doing a compression test on a car engine; it tells you a lot if you know how to interpret the measurements along with all the other clues.

 

Lift angle is 49.

 

240 is not so bad. just a bit "not enough". The problem is when you don't service a watch yourself as I do you never know if it's been fully serviced : train wheel unmounting and cleaning, pallet cleaning and oiling, incas serious cleaning and oiling.

 

Minimum amplitude prescribed after service for caliber 551: 270° horizontal, 240° vertical positions.
However, 290° (V) - 255° (H) is a realistic target.

 

For me, it's more important to have a good beat error than to have perfect amplitude. I mean it causes no damage to the watch. Many horologist don't bother disassembling all the movement as I do automatically. Why : because it take takes time. many of them just clean the train wheel, the pallet and one of the balance inca (the one that is not on the dial side). They just put a drop of oil on the dial side inca if you see what I mean.

 

I think Maurice's (@watchtinker) last two numbers are reversed by a typo.

@Kwijibo you seem to be generous with the term "horologist" for people who only make half a service...

@devnull if I were you, I'd make a full test in 5 positions at full wind (0H) after leaving the watch to settle for 30 minutes. Every time you change position allow a minute for the watch to settle before running the test. Don't forget to set the timegrapher to average over 30 seconds.

Then leave the watch on the bench for 24 hours and run the whole test again (24H). Then you'll get plenty of comments

Anyway, that's what I do and I use this sheet to write in so I can make some sense of the results. Someone will tell you the requirements or, I'll look one of mine up for a Chronometer. Ignore the 12H position.


Alternatively, turn the timegrapher off and you'll probably be much happier in the long run

Cheers, Chris

 

Hi Chris

yes, "horologist" is generous you can't imagine what I sometimes hear. An horlogist appointed by Omega telling me "I don't bother disassembling the whole movement! there's a risk of losing the click spring. I just "wash" them into benzine" I answered : "what about the barrel spring lubrification?". Answer "as you now sir, oil flows, i put some afterwards"
Checking what "says" the watch in 6 positions is a good idea. Set your timegrapher at least on a 30 seconds test duration. and wait a few minutes before havinf sure datas

 

Thanks, Chris, you are right: it is a typo.
The numbers are, obviously: 290° (H) - 255° (V).
Obtaining the correct amplitude depends on the quality of cleaning, assembling, lubrication and, of course, on the conditions of the movement.

 

perfectly right, especially your pallet+anchor wheel, and incas cleaning and lub. Correctly oiling pallets is a pain in the neck but it's a necessary step to hear a watch tick regurarly