WatchUSeek Watch Forums banner

1 - 4 of 4 Posts

·
Registered
Joined
·
4,423 Posts
Discussion Starter · #1 ·
Does anybody know why the METAS test limits would be different for an 8800 movement vs an 8900 movement. I know the power reserve is different, but why other parameters.

I have two Master Chronometer watches...one with an 8900 movement and another with an 8800 movement. I was reviewing the METAS certificates and the test limits are different for the watches. Specifically, I'm interested in the average daily chronometric precision of the watch (one of them says the limit is 0-6 sec/day and the other says 0-5 sec/day), the deviation of chronometric precision in six positions (one says 0-14 sec/day and the other says 0-12 sec/day), and the deviation of chronometric precision between 100% and 33% of power reserve (one says 0-10 sec/day and the other says 0-8 sec/day).

It seems like a certification to a standard for things (timekeeping-related) other than varying power reserves specific to a movement type ought to be the same for all.

Any ideas, thoughts, or outright answers?
 

·
Registered
Joined
·
7,002 Posts
There are actually 3 different standards for METAS. The smaller movements like the 8700 series are 0-7 seconds for average rate, and 16 seconds for the Delta.

It based on movement size. The 8900 is a 13 ligne movement, the 8800 is 11.5, and the 8700 is 9.

The smaller the movement, the looser the specs. COSC has the same thing, looser specs for “Category 2” watches, which are smaller. Category 1 is what everyone knows, so -4 to +6, but category 2 watches are -5 to +8.

Cheers, Al
 

·
Registered
Joined
·
4,423 Posts
Discussion Starter · #3 ·
There are actually 3 different standards for METAS. The smaller movements like the 8700 series are 0-7 seconds for average rate, and 16 seconds for the Delta.

It based on movement size. The 8900 is a 13 ligne movement, the 8800 is 11.5, and the 8700 is 9.

The smaller the movement, the looser the specs. COSC has the same thing, looser specs for “Category 2” watches, which are smaller. Category 1 is what everyone knows, so -4 to +6, but category 2 watches are -5 to +8.

Cheers, Al
That is great information. I was more than a little curious. Why are the specs different? Balance wheel size/inertia? Main spring size? Other? I know only the basics about movements, so this is a good opportunity to learn something.

Thanks for taking the time to respond to the initial question...and thanks in advance for this one!
 

·
Registered
Joined
·
7,002 Posts
That is great information. I was more than a little curious. Why are the specs different? Balance wheel size/inertia? Main spring size? Other? I know only the basics about movements, so this is a good opportunity to learn something.

Thanks for taking the time to respond to the initial question...and thanks in advance for this one!
Yes, basically. Smaller movements are generally more difficult to get good results from then larger movements are, all else being equal.
 
1 - 4 of 4 Posts
Top