Advice between choosing two Seikos and interpreting some data

[Massimo77]

Hello and congratulations for the beautiful forum. I have to choose between two Seikos with caliber 6R35 and I have a question:  Is it better to have a watch that has a high amplitude and, when fully wound, has knocking, or a watch with a lower amplitude but which never goes into rebanking?
In details i have two Seikos with 6R35 movements, I'll show you the results of both on the chronocomparator:

Seiko 1 at full charge:
(dial up) Amplitude 340, +250 s/d,  b/e 0.0  (after a minute circa the values returing in the normal range, amplitude 320, +8 s/d b/e 0.0)
after 30 minutes
(dial up) Amplitude 310, +5 s/d,  b/e 0.0 

Seiko 2 at full charge:
(dial up) Amplitude 290, + 10 s/d b/e 0.5 
after 30 minutes
(dial up) Amplitude 260 , +12 s/d,  b/e 0.5 

so it seems that the Seiko 1 has a problem with rebanking at full charge and then disappearing after about a minute. In light of these data, is the Seiko n.2 to be preferred?

[nevenbekriev]

Where worn on the wrist, probably #1 will overbank alot when spring winds to the end by autowinding, so it is a real problem.

[Waggy]

Overbanking is commonly caused by a problem with the guard pin on the pallet fork, maybe you could take the pallet fork from #2 and put it into #1 and get the best of both worlds? That is assuming you don't wat to attempt to fix the guard pin on #1. Something to consider?

[Klassiker]

I agree with @nevenbekriev. Rebanking is a big problem with an automatic watch, which is going to spend a significant portion of its time on the wrist in a fully wound condition.

Have you had both these watches on your own timegrapher and seen the "rebanking trace pattern" for no. 1? 340 deg. is very high, but could be just shy of rebanking. Also, you need to use the correct lift angle; 53 deg. for the 6R15.

[JohnR725]

On 12/9/2023 at 1:49 PM, Massimo77 said:

I have to choose between two Seikos with caliber 6R35 and I have a question:  Is it better to have a watch that has a high amplitude and, when fully wound, has knocking, or a watch with a lower amplitude but which never goes into rebanking?

Interesting question so which is better to have a defective watch which is not going to keep time. Or watch that's running the way it's supposed to run which will probably keep time?

On 12/9/2023 at 1:49 PM, Massimo77 said:

so it seems that the Seiko 1 has a problem with rebanking at full charge and then disappearing after about a minute. In light of these data, is the Seiko n.2 to be preferred?

Watch number one is defective as the mainspring is supposed to slip and you'd should never have that much amplitude.

Then that means Seiko number two is running correctly and if you are concerned about timekeeping you can adjust the regulation a bit and bring a little closer to zero.

 

[Neverenoughwatches]

On 12/9/2023 at 9:49 PM, Massimo77 said:

Hello and congratulations for the beautiful forum. I have to choose between two Seikos with caliber 6R35 and I have a question:  Is it better to have a watch that has a high amplitude and, when fully wound, has knocking, or a watch with a lower amplitude but which never goes into rebanking?
In details i have two Seikos with 6R35 movements, I'll show you the results of both on the chronocomparator:

Seiko 1 at full charge:
(dial up) Amplitude 340, +250 s/d,  b/e 0.0  (after a minute circa the values returing in the normal range, amplitude 320, +8 s/d b/e 0.0)
after 30 minutes
(dial up) Amplitude 310, +5 s/d,  b/e 0.0 

Seiko 2 at full charge:
(dial up) Amplitude 290, + 10 s/d b/e 0.5 
after 30 minutes
(dial up) Amplitude 260 , +12 s/d,  b/e 0.5 

so it seems that the Seiko 1 has a problem with rebanking at full charge and then disappearing after about a minute. In light of these data, is the Seiko n.2 to be preferred?

Watch 2 is running as it should with good amplitude and probably within Seiko's specified rate parameters . Watch 1 has amplitude issues.

[Massimo77]

Thanks to all for the advices, i just chose the #2 Seiko.