Seiko 6319a , Seiko 2906a amplitude value ?

[Cihan]

Friends, I have serviced Seiko 6319a and Seiko 2906a. I found the lift angles, but what should the amplitude value be? I am reading values between 190 and 200 degrees. Has anyone dealt with these mechanisms? Thanks.

Edited June 12, 2023 by Cihan

[JohnR725]

41 minutes ago, Cihan said:

I have serviced Seiko 6319a and Seiko 2906a. I found the lift angles, but what should the amplitude value be? I am reading values between 190 and 200 degrees. Has anyone dealt with these mechanisms?

What was the watches doing before you service them and it be nice to have numbers beyond timing in one position. Like dial up or down and then crown down for amplitude and if you to picture a timing machine that would be nice?

Seiko typically does not publish their amplitude they did publish it in one of their documents and it's really low. But typically they should do better than what you're seeing there.

 

[wudce]

The Seiko service sheets mention minimum amplitude being 180, which is way too low I feel . Generally after a rebuild, 225-240ish is pretty good. After a few months running they usually settle in the high 240's and can go as high as 270's. in most cases on these Seiko movements.

[Waggy]

I would agree, Seiko amplitudes do seem a little low compared to their Swiss counterparts. 220° is my baseline when just finished rebuild (not based on any science, just seems to be a reasonable number for them) and as @wudce mentions they do better after everything has had a chance to settle in.

Edited August 9, 2023 by Waggy
Typo

[mikepilk]

34 minutes ago, wudce said:

The Seiko service sheets mention minimum amplitude being 180, which is way too low I feel . Generally after a rebuild, 225-240ish is pretty good. After a few months running they usually settle in the high 240's and can go as high as 270's. in most cases on these Seiko movements.

The 180° is with the watch in a vertical position, this is from the 4006 service sheet. 

So horizontal, that's probably 210-220° ?

You may think it too low, but they, the designers of the movement don't 

I agree with @wudce and @Waggy :  about 220 - 240° is fine for these movements. I've spent a long time trying everything to get some movements higher, but they just don't want to.
I have a couple of higher grade movements (23J Lord Matic Cal 5606) which do get 270-280°, but not the bog-standard movements.

[wudce]

I should have said 180 in the vertical position. It's hard to get much better on these older Seiko. Was not long since I did two Seiko 5 with the 6309 movement which both got new mainsprings and both ran in the low 200 in the vertical position. For a 47 year old watch this is not bad.