Rebanking on JLC 889/929

[VWatchie]

7 hours ago, Knebo said:

Wow. These two sentences subtly show the extraordinary level you are at 

Tells me you haven't followed the man very closely!  We're a lucky bunch!  

[Kalanag]

On 1/7/2025 at 12:03 PM, Knebo said:

…

- Yes, it's a spring that presses against the centre seconds pinion to prevent jerking/jumping of the seconds hand.
- But no, in this movement it's not from the top (like Omega 55x or older Rolex), but from the side. Here's a picture of the underside of the barrel bride. The green dot would indicate the place where the centre seconds pinion will be located and the green arrow the direction that the spring pushes against it. I find this solution more elegant and less tricky to adjust than the "from the top" ones. On the other hand, one has to be a bit careful when installing the bridge (see technical guide comment on Fig 7). 

 

On my first assembly of this movement, I “managed” to have the spring at the wrong side of the pinion. It can happen easily. The jerking sweep second told me about the mistake.

Edited January 9 by Kalanag

[Knebo]

1 hour ago, Kalanag said:

On my first assembly of this movement, I “managed” to have the spring at the wrong side of the pinion. It can happen easily. The jerking sweep second told me about the mistake.

Yes, it can happen. I was aware of the risk before assembly, having read that part of the manual. It's easy to avoid misplacing it if you nudge the spring in the right direction through the "window" in the bridge. I think the window is designed for that purpose.

[mikepilk]

On 1/7/2025 at 12:12 PM, Neverenoughwatches said:

I think @nevenbekrievmade his point then, the UK has had quite a few 0°C this year, quite tolerable really....for me anyway. At 0°C HP1300 has 3x the consistency of honey and half that of treacle at normal room temperature.  If the balance gets anywhere near 0°C then it ain't moving. My next experiment is to oil bal cap jewels with honey . 

As it is -3°C this morning, and I'm currently wearing my latest project for timing (Memostar AS 1931), I decided to measure the case temperature after a walk, to see if the oil turns to treacle as you and Nev suggest. 

Using a thermocouple, the case temperature measured 25°C. Not surprising, as body temperature is about 36°C, metal is an excellent heat conductor in close contact with skin, and the watch is under clothing.

So no need to worry about oil turning to treacle 

[nevenbekriev]

What I mean is that a person (may be customer) may leave His watch in a cold room or another cold place for awhile, may be whole  night, and then find it has lost several minutes or even stopped. Then go and explain Him that the watch has to be always hot in order to run normally...

[Knebo]

5 hours ago, nevenbekriev said:

What I mean is that a person (may be customer) may leave His watch in a cold room or another cold place for awhile, may be whole  night, and then find it has lost several minutes or even stopped. Then go and explain Him that the watch has to be always hot in order to run normally...

Alright alright, I just put the watch in the garage. I'll see tomorrow morning if it gained/lost a lot of time. I'll also take an amplitude reading tomorrow when I get it from the garage - and then after it warms up. 

I'll report back! 

[nevenbekriev]

Probably if Omega recommends this solution, then it should be OK. Just curious if/how the amplitude changes.

[Knebo]

Ok, results are in @nevenbekriev, @mikepilk, @Neverenoughwatches et al. 

1. The watch didn't lose/gain more time in the garage than in my watch drawer. 

2. Amplitude loss when at 5°C (garage) vs 22°C (after warming it up) is 20°.

Straight from the garage:

After warming up:

(note: background lightning difference is due to curtains being closed/open) 

[Neverenoughwatches]

2 hours ago, Knebo said:

Ok, results are in @nevenbekriev, @mikepilk, @Neverenoughwatches et al. 

1. The watch didn't lose/gain more time in the garage than in my watch drawer. 

2. Amplitude loss when at 5°C (garage) vs 22°C (after warming it up) is 20°.

Straight from the garage:

After warming up:

(note: background lightning difference is due to curtains being closed/open) 

Good Experiment Knebo,  interesting that it was starting to reduce the amount of swing just not enough to affect the rate. I wonder if with 9010 it would be the same ?.........if you'd be so kind as to.......

Just dont take it with you on any Antarctic expeditions you might have planned