Watch loses time during day/date change

[GuyMontag]

I serviced an automatic day/date watch (Bulova 11AOACD) and it is keeping decent time ( -9 to -21 seconds/day across all positions) but I have a few questions because of an issue during the day/date change. However, the amplitude was only ~258 in Dial Up and Dial Down positions and about 230 to 235 in all vertical positions. I didn’t notice any excess barrel side-shake during inspection. Regarding the low amplitude I thought perhaps I over-greased the barrel. This barrel has eight notches in the barrel wall and I added grease to the left of each of those (the mainspring has a clockwise orientation in the barrel); the photo shows the amount and location (Kluber P125). 

 

Question 1: Is it correct to add grease at every notch in an automatic watch, regardless of the number of notches? If so, for a barrel with 5 notches you would grease at those 5 notches and a barrel with 12 notches (for example), you would grease at all 12 notch locations?

 

This issue the watch is showing is that the watch starts losing time (and amplitude) during the day/date change. The day wheel starts moving at around 10:50PM.  I put the watch on the timegrapher and took a photo every 60 seconds starting at 10PM until 11:33 when the watch stopped. Only the hour and minute hands stopped, the second hand still moved. The previous two nights it didn't stop, it just showed it lost about 35 minutes during the night:

 

Question 2: Is the issue being caused by a loose cannon pinion and/or something else, such as an over-greased barrel?  If I manually advance the day/date by setting the time past 12 AM, the rate improves to ~ -9 seconds/day and the amplitude goes back up to 250+.
 

This movement has an offset cannon pinion. When I removed the friction pinion prior to cleaning it I accidentally removed the entire arbor with both the pinion and friction pinion from the wheel. Oops. I grabbed another one from a donor movement... and the same thing happened. I was able to rivet that one back on the wheel, but I then noticed that the friction pinion was incredibly loose. So I ended up grabbing another one out of a watch that I serviced a month or so ago. I just dropped this one into the movement and carried on.

 

Question 3: Is it possible to tighten this style of friction pinion? The photos below show how it is arranged. The friction pinion has an inset at the top that a brass washer/ring fits into. Both the friction pinion and the brass washer require a small force to get them to "snap" onto the arbor. The last photo shows my two smallest round faced punches with the smallest one just fitting into the inset part of the friction pinion. I have some smoothing broaches on order so once they arrive I will give this a shot regardless, but I'm wondering if anyone has had success tightening this style of friction pinion? Will the fact that it is steel make it difficult to close the hole?

 

Edited February 21, 2023 by GuyMontag

[GuyMontag]

Does anyone happen to have any suggestions on why the amplitude is dropping and the watch losing time during the day/date change, and if the cannon pinion can be tightened and is the barrel perhaps over greased?

[HectorLooi]

As for the hands stopping at 11.33, that is probably due to a loose friction pinion. I'm not sure if there's any way to tighten a friction pinion of this design.

I checked with my mentor whether it is normal to lose amplitude when the calendar works engage, he said that that's an interesting question. He never thought about it. He said logically there should be a slight drop in amplitude but it shouldn't be so great as to affect time.

Overgreasing the barrel would cause premature slippage of the bridle, resulting in lower amplitude and shorter power reserve.

My mentor never used braking grease. He just uses regular 8200. I switched to using a strong braking grease and experienced something strange. The spring would hold a wind of maybe 15 - 20 winds, then suffer a major slippage and lose most of the power. I'm not sure if am over or under greasing the barrel wall.

Has anyone experienced this?

[Nucejoe]

Did you lubricate the groove  day/ date disc fits on? 

Are you sure the day or date disc or a teeth of them is not bent ?

Do you have the right " U " spring in the jumper assembly? 

Instead of tightening canon pinion, I try puching the section of the arbour it fits on to an oval shape.

 

[GuyMontag]

13 hours ago, HectorLooi said:

As for the hands stopping at 11.33, that is probably due to a loose friction pinion. I'm not sure if there's any way to tighten a friction pinion of this design.

I checked with my mentor whether it is normal to lose amplitude when the calendar works engage, he said that that's an interesting question. He never thought about it. He said logically there should be a slight drop in amplitude but it shouldn't be so great as to affect time.

Overgreasing the barrel would cause premature slippage of the bridle, resulting in lower amplitude and shorter power reserve.

My mentor never used braking grease. He just uses regular 8200. I switched to using a strong braking grease and experienced something strange. The spring would hold a wind of maybe 15 - 20 winds, then suffer a major slippage and lose most of the power. I'm not sure if am over or under greasing the barrel wall.

Has anyone experienced this?

I think I'll check another watch with the same movement to see what happens to the amplitude during the date change. I would have thought that if the amplitude is decreasing, shouldn't the rate increase?

 

10 hours ago, Nucejoe said:

Did you lubricate the groove  day/ date disc fits on? 

Are you sure the day or date disc or a teeth of them is not bent ?

Do you have the right " U " spring in the jumper assembly? 

Instead of tightening canon pinion, I try puching the section of the arbour it fits on to an oval shape.

 

I followed the tech sheet for the movement. It didn't show lubrication of the groove the day/date fits on. I have serviced a few other of these movements and haven't seen this issue.

I didn't see any bent teeth but will double check.

The date jumper spring is the correct one (there day jumper is riveted to the plate) in the correct orientation.

Widening the arbor is an interesting idea. I think I'll try closing the hole of the friction pinion first and if that isn't working then I'll try widening the arbor. My concern would be that if I flatten it too much I'm not sure how I would then file the arbor back.

[Nucejoe]

1 hour ago, GuyMontag said:

I think I'll check another watch with the same movement to see what happens to the amplitude during the date change. I would have thought that if the amplitude is decreasing, shouldn't the rate increase?

 

I followed the tech sheet for the movement. It didn't show lubrication of the groove the day/date fits on. I have serviced a few other of these movements and haven't seen this issue.

I didn't see any bent teeth but will double check.

The date jumper spring is the correct one (there day jumper is riveted to the plate) in the correct orientation.

Widening the arbor is an interesting idea. I think I'll try closing the hole of the friction pinion first and if that isn't working then I'll try widening the arbor. My concern would be that if I flatten it too much I'm not sure how I would then file the arbor back.

Usually bent disc scratch the groove which might not be spotted unless  under high magnification, even in  case of no scratch ,  you really  can't go wrong  greasing the groove,  a bent disc or a teeth of it might have  gone un-noticed.

I have no experience closing a hole in a pinion this thick, have a gut feeling you might deform it before the hole gets peened enough.

A go-no go check as you widen the arbour should suffice, let call tight enogh- not tight enough can pinion.

I don't think the barrel greased or not is causing this problem, mainspring must be badly set to cause this. 

Good luck

 

 

[GuyMontag]

2 hours ago, Nucejoe said:

Usually bent disc scratch the groove which might not be spotted unless  under high magnification, even in  case of no scratch ,  you really  can't go wrong  greasing the groove,  a bent disc or a teeth of it might have  gone un-noticed.

I have no experience closing a hole in a pinion this thick, have a gut feeling you might deform it before the hole gets peened enough.

A go-no go check as you widen the arbour should suffice, let call tight enogh- not tight enough can pinion.

I don't think the barrel greased or not is causing this problem, mainspring must be badly set to cause this. 

Good luck

 

 

It could be the mainspring itself as I forgot that when I was removing the arbor from the winder the spring unwound itself and was all tangled. I untangled it but didn't notice the spring being deformed in any way but I may have missed something.

What punches would you use to widen the arbor?