Correct amplitude for KS 5626-7000?

[a49]

Wonder what the amplitude should be on a Seiko KS caliber 5626? I am aware that the amplitude is different depending on factors such as, age, year of service etc, but approximate?

Thanks in advance,

[inboost]

Hello a49 ,

I have this watch and although not serviced by me was serviced not so long ago by a good friend. Upon arrival at full wind I found it about 240° with a lift angle of 56°. When the watch is perpendicular to gravity then it drops a normal-ish 20° of amplitude in any of the crown up positions.

[a49]

Hello WS Benefactor,

And thank you for your information. Great to know the lift angel is 56 on KS and you got a fine amp there in 240 degrees. I´ve heard that the Seikos have a little bit lower amplitude compared with the swiss tough I cant veryfy source on that statement. My KS 5626 have an amp of 206 and and a beat error of 0.6 ms. So I guess its not to bad but time for a service this year. Btw lovley KS you got. 

[inboost]

Hi there a49,

Yes I'd agree that vintage Seiko watches do tend to post lower amplitudes, but this may be more the fault of wear and tear than actual design. It's a touchy subject (amplitude) as it can be maddening to correct and easily misinterpreted by time graphing equipment due to the audio signatures that must be interpreted to accurately to measure them.

If it is in your capabilities, you might take the movement out of it's case and then try it on the time grapher again. This would be an easy time to adjust rate and beat error if you are comfortable doing that work. The neat thing about the 5626-7000 is that the rate can be adjusted from outside of the case. There is a plug (screw) just under the lug which is removed and then the rate adjuster becomes accessible.

Inboost

[HiBeat]

for lift angles, probably just coincidence, but a 52XX series is 52 degrees lift angle and the 56XX series is 56 degrees.  Easy to remember.

The whole amplitude obsession is, in my opinion, because Rolex can go over 300 degrees regularly. I think their marketing team made us think mid-200's is somehow lacking.   For any serviced Seiko I have ever owned if you can get 240 degrees dial up/dial down I think you stop worrying and start enjoying.

[saldog]

In my experience, 50 and 60 series Seikos are fine and dandy with anything over 220º amplitude. It is rare to get 260º+, but I've been lucky enough to have a few in that range, so it is possible.

The 70 series movements, including 7S26/36 and later 4R36 movements are around 275º-295º amplitude in good health, but if I had just serviced one and was getting 250º, I wouldn't spend too much time hunting for better.

I read somewhere that the locking depth of the pallets is one of the reasons for Seiko's low amplitudes. This was based on Seiko's concern over their ability to reliably manufacture pallet forks in large numbers and be able to loosen up the tolerance on stone placement. This might also explain the variability that we see in the real world. You can buy two new Seikos with the same movement and see 10-20º difference in amplitude.

What is important about amplitude is not that it is high or low, but is it where it should be for the watch's design? You can't compare the amplitude of two completely different watch designs and think of amplitude as some spec like horsepower, where the higher it is, the better it is. A watch will keep running even at 180º or sometimes less than that.

We pay attention to amplitude simply because we want to know if a watch is healthy or if it needs servicing. We compare the observed amplitude to what it "should be", which actually is what a49 is asking and why this is a good question to ask. While I own a few 51xx and have serviced them, I don't own any 52 or 56 like in the KS's but I hope to one day and knowing that the amplitude seems to be in line with other Seiko movements of the day, these responses are helpful.

[Myles]

Jan 19, 2024 9:00:25 GMT -8 HiBeat said:

for lift angles, probably just coincidence, but a 52XX series is 52 degrees lift angle and the 56XX series is 56 degrees.  Easy to remember.

The whole amplitude obsession is, in my opinion, because Rolex can go over 300 degrees regularly. I think their marketing team made us think mid-200's is somehow lacking.   For any serviced Seiko I have ever owned if you can get 240 degrees dial up/dial down I think you stop worrying and start enjoying.

My 8L35 shows over 300º, as does my 6R35 (after it was serviced under warranty). 7S26 and 4R36 seem to run in the mid-200s.

[HiBeat]

Jan 19, 2024 9:51:10 GMT -8 Myles said:

Jan 19, 2024 9:00:25 GMT -8 HiBeat said:

for lift angles, probably just coincidence, but a 52XX series is 52 degrees lift angle and the 56XX series is 56 degrees.  Easy to remember.

The whole amplitude obsession is, in my opinion, because Rolex can go over 300 degrees regularly. I think their marketing team made us think mid-200's is somehow lacking.   For any serviced Seiko I have ever owned if you can get 240 degrees dial up/dial down I think you stop worrying and start enjoying.

My 8L35 shows over 300º, as does my 6R35 (after it was serviced under warranty). 7S26 and 4R36 seem to run in the mid-200s.

Agreed on the 8Ls I have a few and flipped a few, all near or above 300 degrees amplitude but not in the vintage world.  It's hype to be overly concerned on the amplitude reaching the magical 300, I think it's a marketing ploy of the Swiss.

Oh yeah, my 3135 Datejust runs 330

[HiBeat]

And today I received a customer's old SKX007 in for some mod work. As always first things first, check the movement before removing.

This is an 8 year old 7S26C never serviced or regulated !

[appumaster]

I remember reading about the fact that somehow mathematically poise errors cancel each other out at 220° amplitude. I did read that about 7-8 months ago and I didn't understand it then. saldog 's comment reminded me of it. In that sense, maybe the logic of 'lower amplitude by design' would also make sense for the mass market.
I'll dig out the theory book(s) and go over it. Maybe I'll understand it better this time.