Timing tolerances - a guide to understand how they work

Archer · Jan 28, 2019

P POC67
From my limited experience, an automatic watch will run slower as it get older.

That’s not an assumption I would make for every watch, as many things will go into how a watch changes in timing over time.

Cheers, Al

stefman · Jan 29, 2019

Great explanation by @Archer and interesting thread. Stumbled upon it during a search because I find my Speedy seems to be starting to run a bit fast, which I interpret as a servicing is coming up. It’s seems to be running about 9 seconds fast. A few months ago when I tested it, it was running 5 seconds fast.

gostang9 · Aug 12, 2019

BUMP for a great thread that some may not have seen yet. So often people post about how their watch is keeping time, what the COSC / METAS standards mean, etc. The OP from @Archer does a great job explaining just what it means when an official result of timing tolerances is given by a proper watchmaker and why our real world experiences may be confusing if we don't understand what it means... 📖

👍

PhilF · Oct 3, 2019

stefman
Great explanation by @Archer and interesting thread. Stumbled upon it during a search because I find my Speedy seems to be starting to run a bit fast, which I interpret as a servicing is coming up. It’s seems to be running about 9 seconds fast. A few months ago when I tested it, it was running 5 seconds fast.

If you haven't resolved this, check your Speedy and see if it's magnatized, mine was running +10/day, after demagnitized +1.5.

whyboddau · Oct 3, 2019

Thank you Al! This is very informative! Great write up!

Wryfox · Oct 3, 2019

PhilF
If you haven't resolved this, check your Speedy and see if it's magnatized, mine was running +10/day, after demagnitized +1.5.

These days with strong neo magnets on everything (like your ipad case, phone holder, etc) it is VERY easy to magnetize a mechanical watch. Magnets are everywhere. Beware. A guy was next to me at a store counter last weekend, flipped open his ipad case and the magnet flap flopped open right next to my wrist. I must have looked like I had a seizure.🤪

About 1/3rd of the vintage watches I buy are magnetized to the extent it affects timing. Much higher percentage on mail order watches..maybe due to shipping scanners?

Professor · Oct 3, 2019

Archer
That’s not an assumption I would make for every watch, as many things will go into how a watch changes in timing over time.

Cheers, Al

Could wear to the jewels or teeth of the escapement speed up the timing?
Also if the lube between shafts and bearing jewels was thickened slowing the moving parts and the timing adjusted to compensate, then later on the lube dried completely and flaked away leaving only metal to jewel contact could the watch run faster for awhile till friction set in?

stefman · Oct 4, 2019

PhilF
If you haven't resolved this, check your Speedy and see if it's magnatized, mine was running +10/day, after demagnitized +1.5.

Thanks, I’ll get it checked.

Archer · Oct 4, 2019

Professor
Could wear to the jewels or teeth of the escapement speed up the timing?
Also if the lube between shafts and bearing jewels was thickened slowing the moving parts and the timing adjusted to compensate, then later on the lube dried completely and flaked away leaving only metal to jewel contact could the watch run faster for awhile till friction set in?

The things you mention would affect amplitude. But the relationship between amplitude and timekeeping can be quite complex. As I said there are a lot of factors that go into a watch speeding up or slowing down with amplitude changes. Without knowing the exact details of how a particular watch is set-up speculating how the timekeeping would change is rather pointless.

Hduck · Oct 4, 2019

Archer
The things you mention would affect amplitude. But the relationship between amplitude and timekeeping can be quite complex. As I said there are a lot of factors that go into a watch speeding up or slowing down with amplitude changes. Without knowing the exact details of how a particular watch is set-up speculating how the timekeeping would change is rather pointless.

A,

I am considering getting a simple tester off Amazon to get the rates for my watches in various positions so I can adjust for the wearing. I've noticed that lift angle seems to be a part of the process. Coming at the process as a newbie, and probably speaking pure gibberish, I saw videos on YouTube that seemed to have people adjusting the timer to 180 degrees to get the lift angle on the readout. Am I interpreting this correctly?

Perhaps there is a list of lift angles for some of my calibers? Valjoux 7750, Breitling 01 Omega 1861, 3861, and 9900? So I could skip this process?

H

Archer · Oct 4, 2019

Hduck
A,

I am considering getting a simple tester off Amazon to get the rates for my watches in various positions so I can adjust for the wearing. I've noticed that lift angle seems to be a part of the process. Coming at the process as a newbie, and probably speaking pure gibberish, I saw videos on YouTube that seemed to have people adjusting the timer to 180 degrees to get the lift angle on the readout. Am I interpreting this correctly?

Perhaps there is a list of lift angles for some of my calibers? Valjoux 7750, Breitling 01 Omega 1861, 3861, and 9900? So I could skip this process?

H

Lift angles affect the balance amplitude reading, and there are many lists of them out there on the internet.

You only do the procedure you mention if you don't already know the lift angle - the process involves visually confirming that the balance is rotating 180 degrees each way from rest, then setting the lift angle on the timing machine until the balance amplitude reads 180. Slow motion video from a phone can really make this process quite easy.

Here's a list of lift angles to get you started:

https://www.lepsi.ch/lift-angle/

Of course with all such information on the internet, use at your own risk. It's always better to verify lift angle with the manufacturer if you can - typically if you email them they will provide it.

Edit to add that the cheap timing machines will not give you correct balance amplitude for Omega co-axial movements, or the Audemars Piguet escapement - these require specific programming that as far as I know only professional timing machines have.

Cheers, Al

Hduck · Oct 4, 2019

Archer
Lift angles affect the balance amplitude reading, and there are many lists of them out there on the internet.

You only do the procedure you mention if you don't already know the lift angle - the process involves visually confirming that the balance is rotating 180 degrees each way from rest, then setting the lift angle on the timing machine until the balance amplitude reads 180. Slow motion video from a phone can really make this process quite easy.

Here's a list of lift angles to get you started:

https://www.lepsi.ch/lift-angle/

Of course with all such information on the internet, use at your own risk. It's always better to verify lift angle with the manufacturer if you can - typically if you email them they will provide it.

Edit to add that the cheap timing machines will not give you correct balance amplitude for Omega co-axial movements, or the Audemars Piguet escapement - these require specific programming that as far as I know only professional timing machines have.

Cheers, Al

Much appreciated! I guess I run the risk of trying to be too technical in simply trying to find the best positions for regulating overnight off the wrist.

Howard

Archer · Oct 4, 2019

Hduck
Much appreciated! I guess I run the risk of trying to be too technical in simply trying to find the best positions for regulating overnight off the wrist.

Howard

If that's all you want to find, then fully wind your watch, note down the time relative to a known good time source, let it sit in one position for 24 hours, and note the gain ir loss. Repeat for the other 5 positions, and you will have the information you need.

Deafboy · Oct 4, 2019

Hduck
A,

I am considering getting a simple tester off Amazon to get the rates for my watches in various positions so I can adjust for the wearing. I've noticed that lift angle seems to be a part of the process. Coming at the process as a newbie, and probably speaking pure gibberish, I saw videos on YouTube that seemed to have people adjusting the timer to 180 degrees to get the lift angle on the readout. Am I interpreting this correctly?

H

I use this method regularly. Another useful amplitude is 270 degrees because, like at 180 degrees, the arms of the balance wheel overlap at the peak motion of the balance wheel (this applies to a two arm balance wheel).

Note that older watch models do not have published lift angles because the banking pins are adjustable, the adjustment of which affects lift angle.

Deafboy · Oct 4, 2019

Hduck
Much appreciated! I guess I run the risk of trying to be too technical in simply trying to find the best positions for regulating overnight off the wrist.

Lift angle is to determine amplitude - does not affect rate.

Archer · Oct 4, 2019

Deafboy
Note that older watch models do not have published lift angles because the banking pins are adjustable, the adjustment of which affects lift angle.

Not really. It's actually because when the older watches were made, timing machines that told you the amplitude didn't exist yet. Back then, watchmakers relied on eyeballing the amplitude to see if the balance had "good action" and if it looked okay, they moved on. Timing machines with amplitude are a relatively recent development in watchmaking.

BTW, unless you know what you are doing, leave the banking pins alone...not really any need to move them once they are set at the factory.

take57 · Oct 4, 2019

Just tossin' it out here but I wonder if the benevolent overlords that run this fine website would consider slapping together a sticky or super-thread that consists of Archer's always welcome and endlessly informative "How and why" guides. They are just too good to be randomly scattered across the vast Omega Forums empire. Keep up the good work !!!

Hduck · Oct 4, 2019

take57
Just tossin' it out here but I wonder if the benevolent overlords that run this fine website would consider slapping together a sticky or super-thread that consists of Archer's always welcome and endlessly informative "How and why" guides. They are just too good to be randomly scattered across the vast Omega Forums empire. Keep up the good work !!!

This would be great. I’ve just joined within the past few weeks and was not aware of his great threads and posts

Deafboy · Oct 4, 2019

Archer
Not really. It's actually because when the older watches were made, timing machines that told you the amplitude didn't exist yet. Back then, watchmakers relied on eyeballing the amplitude to see if the balance had "good action" and if it looked okay, they moved on. Timing machines with amplitude are a relatively recent development in watchmaking.

Fair enough. Though my guess a movement model with movable banking pins would probably have a wider range of lift angles from sample to sample than a model with fixed pins.

Archer · Oct 4, 2019

Deafboy
Fair enough. Though my guess a movement model with movable banking pins would probably have a wider range of lift angles from sample to sample than a model with fixed pins.

Why?