Watham Grade 161 Timing screws...etc

[LittleWatchShop]

The watch came to me in bad shape...broken third wheel, pallet fork, escape wheel, staff, and twisted balance wheel.  The hands were also missing.  Somebody stuck a Craftsman screwdriver into it, no doubt...thinking they could repair it...lol.

Anyway, I found a replacement movement with hands and all, so I replaced the entire movement and kept the original dial.

Full service of the movement followed and I had some issues with the hairspring.  I got it running pretty true and was getting what I think is good amplitude--full 360 degree rotation.

But it was running slow.  Minimum throttle on the regulator and just way slow.  So I removed a pair of timing screws--the point of this post.  Notice in the picture that the screw I removed is a very bright brass whereas the other timing screws are a dull brass.  I assume brass in both cases.  Are these two screws different than the other timing screws?

They attached at the balance beam and I was going to leave them off and compensate for timing by adding timing screws in other locations.

Is this the best course of action?

[nickelsilver]

That looks like a meantime screw, should be a light friction fit on the threads, and is used to adjust the rate in addition to the regulator. Usually isn't screwed all the way in, should stay with the balance. Check other screws for timing washers and remove those, see how it does. If you need to remove weight still you can trim other screws as needed.

 

360 degrees isn't possible, were you looking at the timing machine's amplitude or the watch itself? The lift angle on some of these is quite low, even below 40; if you're set to 52 you'll get an artificially high reading.

[LittleWatchShop]

1 minute ago, nickelsilver said:

360 degrees isn't possible, were you looking at the timing machine's amplitude or the watch itself? The lift angle on some of these is quite low, even below 40; if you're set to 52 you'll get an artificially high reading.

I took a slow motion video and will upload it shortly and provide a link.

 

3 minutes ago, nickelsilver said:

Usually isn't screwed all the way in

They were screwed all the way in and unusually tight.  Tried to just use a pin vise designed for this purpose, but they were too tight, so I used a screwdriver.  I will put them back in as you suggest.

Here is the video.

[Marc]

That's a full 360 rotation, but only 180 degrees amplitude, which is not that good at all.

Balance wheel amplitude is the angle of rotation from the neutral point (where the wheel would be sitting if the balance was at rest with no power on) and either one of its extremes of rotation (the point where it reverses direction), so half the total rotation from one extreme to the other.

If the amplitude was 360 then the balance would rotate a full 720 degrees from its extreme clockwise position to its extreme anticlockwise position, which as @nickelsilverpoints out, is impossible as the pallet fork would be in the way and hard up against the banking. You would get re-banking, with the impulse jewel crashing into the outside of the fork horns causing the balance wheel to rebound. Sounds like a galloping horse.

[LittleWatchShop]

10 minutes ago, Marc said:

That's a full 360 rotation, but only 180 degrees amplitude, which is not that good at all.

Yeah, I recall seeing this definition, but had forgotten it.  Back to the drawing board.

BTW, I determined that it was running fast but measuring on my oscilloscope using my DIY sensor/amplifier.  I measure a full period so that any beat error is compensated.

I put the two timing screws back in and now the amplitude is reduced and the watch is timing slower.

[JohnR725]

4 hours ago, LittleWatchShop said:

what I think is good amplitude--full 360 degree rotation.

as others have stated 360° is a very undesirable amplitude. I think usually about 320 is the maximum because anything over he you will have bad things happen.

4 hours ago, nickelsilver said:

360 degrees isn't possible, were you looking at the timing machine's amplitude or the watch itself? The lift angle on some of these is quite low, even below 40; if you're set to 52 you'll get an artificially high reading

yyes the problem of vintage watches they don't give us a lift angle.. Then yes from the ones that I've measured they can vary by quite a bit and it's really independent of their size.. The ones I've figured out range from anywhere from 38 to 62°..

tthen in addition to lift angle problem if you amplitude is super low often times the timing machine  will look at the middle part of the waveform and give you an abnormally high number. Which means visually your amplitude has to agree with the machine or the machine is having a problem..

 

4 hours ago, LittleWatchShop said:

Notice in the picture that the screw I removed is a very bright brass whereas the other timing screws are a dull brass. 

then as others have pointed out that appears to be a mean time screw it's not supposed to ever come out. They're not supposed to be screwed in tight either but sometimes you find him that way. Another way to tell is usually the threaded part is longer. Then of course the thread dimensions are entirely different the usually much finer and are designed to stay in place hopefully. The word hopeful is because of they get played with too much they get loose.

https://pocketwatchdatabase.com/search/result/waltham/15644188

obviously not your serial number but close enough. Being as it's a seven jewel watch of that size I'm suspicious as to whether it has a mean time screw or not? because usually mean time screws are associated with better grade balance wheels which would never be found on a seven jewel watch especially of this size. It's possible that somebody is mixing and matching  components before you  and shoving and whatever they had.

 

 

 

[LittleWatchShop]

33 minutes ago, JohnR725 said:

They're not supposed to be screwed in tight either but sometimes you find him that way. Another way to tell is usually the threaded part is longer. Then of course the thread dimensions are entirely different the usually much finer and are designed to stay in place hopefully. The word hopeful is because of they get played with too much they get loose.

As noted earlier, they are very tight.  I have reinstalled them in the same location from where they came.  However, shortly after that I had to leave my little watch shop for a short trip.  Will get back to it on Sunday afternoon at the earliest. 

Now that I know what they are called, I found this forum thread is quite informative.

Edited May 13, 2022 by LittleWatchShop

[Nucejoe]

 Does this vid show the actual speed?   I wonder if its like a vid we had  before that wasn't a vid but some sort of GIF whatever and the speed looked abnormally slow. 

 

[LittleWatchShop]

11 minutes ago, Nucejoe said:

 Does this vid show the actual speed?   I wonder if its like a vid we had  before that wasn't a vid but some sort of GIF whatever and the speed looked abnormally slow. 

 

No, it is a slow motion video taken with my android phone. Super slomo.