Vintage watch regulation question

[Feedback]

Hi All,

I've been working an old, well-used Landeron 48 movement. The chronograph parts aren't installed yet because I'm trying to make sure I'm happy with the performance of the primary timekeeping components before I start layering that stuff onto the bridges. In any event, the watch is running fairly well overall, with around 300 degrees of amplitude and reasonably steady output on the timegrapher, but having done a first quick pass at regulation I've found that the watch wants to run fast and I've had to adjust the regulator to the far reaches of the "slow" range in order to get close to correct timekeeping, as you can see in the photo below. Since this is an older movement the relationship of the regulator and the adjustment arm/indicator is fixed. It may just be my OCD but I'd really like to get the watch to regulate with the adjustment arm+ closer to the center of the range. I've tried loosening the regulator pins, and that helped a bit, but not nearly enough to fully correct the issue.

Question: Is there some other technique I should be trying here, or is this just the kind of "old watch stuff" where it's better to shrug and move on?

Visually, the hairspring looks great, is concentric and flat, and is pulsing the way you would expect. The beat error is a bit off but not terrible - between 1 and 2ms. Ordinarily I'd let that slide on a watch like this because adjusting it doesn't seem to be worth the risk of repeatedly messing with the balance, but is it possible that's the culprit, or part of it? I could potentially loosen the regulator more, but again I don't want to risk breaking a pin, so it's not something I would attempt without confidence that it's going to make a substantial difference.

I can certainly move forward with the watch as is, and the timekeeping performance I can get out of it will be more than acceptable for an ~80 year old watch, but I'd love to tap into the collective wisdom here in case I'm missing something obvious...

 

Edited October 5, 2024 by Feedback
Typo fix

[JohnR725]

sometimes I have a lack of reading skills because today I'm not seeing a number attached to just how fast you're going? Then 300° amplitude for a vintage watch how did you achieve that? then I was like to see pictures the timing machine results. Plus is dial-up and dial down identical for timekeeping and what happens if you put the watch  new one of the crown positions like crown down. Then as it's a mechanical not an automatic watch we wind it up nice and tight you getting at 300° amplitude digital at the watch settle for about 15 minutes before you looked at the timekeeping? Because you usually want the watch settle a little before you time it.

[praezis]

Which lift angle did you choose? If the default 52 then your real amplitude is 240 - if no other measurement errors apply.

You should do the tests that John recommends, before any advice can be given.

Frank

[nickelsilver]

Yes, the lift angle should be 42 on this piece.

 

Check that the regulating pins have a visible gap with the hairspring, between 1/2 to 1 hairspring thickness, and, importantly, that the spring is centered well between them. With no power on the watch, just a little movement of the balance should cause the spring to bounce from one to the other.

 

If the spring wants to stay in contact with one pin, this can cause an increase in rate. But- once the amplitude goes above a certain amount, the spring may begin to come away from the pin. This can cause all sorts of timing issues.

 

If all is well, and you want to reduce the overall rate, the easiest and best solution would be to add a pair of timing washers under opposing balance screws.

[Nucejoe]

Lift angle is 42 according to Ranfft.

 

8 hours ago, Feedback said:

Visually, the hairspring looks great, is concentric and flat, and is pulsing the way you would expect. 

  It can still be intermitantly sticking, a vid then watched  it in slo- mo helps make sure.

This is a COSC timekeeper, how fast is it running?  Highest delta too or daily rate in all positions.

Agree ,  great advice by JohnR , do the tests he outlined.

Rgds 

  

 

[mikepilk]

Is the hairspring hitting the centre wheel ?

[Nucejoe]

1 hour ago, mikepilk said:

Is the hairspring hitting the centre wheel ?

 Off to my optometrist.

[Feedback]

Thanks everyone. After reading all of this I decided I needed to be a little more aggressive adjusting the inner regulator pin, and that seems to have done the trick. Right now the watch is running (dial down) at ~0 s/d with the regulator arm nearly centered. With the lift angle set correctly the amplitude reads at a more realistic ~245 degrees, with 1.3ms beat error. I'm definitely losing quite a bit of amplitude (and a signficantly faster rate) when I run it dial-down, so I still have some work to do. I'm going take the balance off, re-clean/oil the top jewel, re-tighten the regulator just a hair, polish the pivots, and perhaps tweak the hairsping collet to see if I can improve that beat error. Hopefully that will put my close to where I want to be before I move on to re-assembling the chronograh components.

Thank you again for all of the helpful advice!

By the way, the hairspring may indeed have been tapping the center wheel (just barely), but looks like it's got a bit more clearance since my most recent adjustment to the regulator. It's definitely a tight tolerance!

Edited October 5, 2024 by Feedback