Meantime Screws

[jdrichard]

I am working on a beautiful 21 Jewel Gold Splashed Elgin movement and it is running way to fast, past the adjustment leaver. So the question is, do I just unscrew the meantime screws on the balance (2 Screws, equal turns) or do I also do the Quarter Screws?

The balance is in beat after I adjusted the collet (approx .5 ms).

 

 

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[Tmuir]

The ones on the arms are know as 'Mean Time Arm screws' and the ones in the middle are 'Meantime Rim Screws'.

I've never had to do this but when you think about it you must adjust all 4 equally or the balance will go out of poise.

Henry Fried's book says half a turn can give or take out to a minute a day.

[Tmuir]

I've just noticed in the photos it looks like the mean time screws are all screwed in flush with the rim of the balance, usually they are unscrewed slightly from factory to regulate the watch, the fact they are all screwed in makes me think someone has fiddled with it.

[nickelsilver]

I only see 2 meantime screws at the arms, no other "adjustable" screws. If you have 4 you very much can move them in pairs, no need to touch all 4. Start with quarter turns, and see what the result is. If you get more than maybe 3 turns out from the rim you should try adding timing washers (in pairs, opposing screws of course).

[jdrichard]

I've just noticed in the photos it looks like the mean time screws are all screwed in flush with the rim of the balance, usually they are unscrewed slightly from factory to regulate the watch, the fact they are all screwed in makes me think someone has fiddled with it.

I agree. The watch was running way too fast. I have turned all 4 screws and perhaps only needed to turn the Meantime Screws. I have around 2 turns on the meantime and 1 turn on the rim screws. The rim screws feel a bit loose and I may screw them back in and just work with the Meantime screws.


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[jdrichard]

I only see 2 meantime screws at the arms, no other "adjustable" screws. If you have 4 you very much can move them in pairs, no need to touch all 4. Start with quarter turns, and see what the result is. If you get more than maybe 3 turns out from the rim you should try adding timing washers (in pairs, opposing screws of course).

Very good advice. I do have timing washers and may add a set to the meantime screws to set the regulator arm in the middle.


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[nickelsilver]

Just now, jdrichard said:

I agree. The watch was running way too fast. I have turned all 4 screws and perhaps only needed to turn the Meantime Screws. I have around 2 turns on the meantime and 1 turn on the rim screws. The rim screws feel a bit loose and I may screw them back in and just work with the Meantime screws.


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I don't see any adjustable screws apart from the 2 at the arms, so it's normal they'd feel loose if you did others. Meantime screws will always have longer threads than the rest.

[jdrichard]

I don't see any adjustable screws apart from the 2 at the arms, so it's normal they'd feel loose if you did others. Meantime screws will always have longer threads than the rest.

I think i "screwed" up. I screwed back the quarter screws as well and I don't think they are quarter screws. Plan B is to screw them back in and turn out the meantime screws one or two more turns...add washers if I have more than 3 turns as recommended and see where I get. BTW, I'm doing this with the balance in place but hold it carefully with tweezers. Any issue there?

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[nickelsilver]

BTW, I'm doing this with the balance in place but hold it carefully with tweezers. Any issue there?

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Well you're risking the pivots if you end up putting too much pressure, but it is done that way by many.

[jdrichard]

Well you're risking the pivots if you end up putting too much pressure, but it is done that way by many.

I am being very careful. The watch has a 550 deg swing, amazing amplitude (270). So after 2 days the watch stopped. The non-quarter screw that I accidentally turned, thinking it was a timing screw as well, turned out on it’s own and ended up touching the balance cock. So I tightened the screw and it’s brother and turned the Meantime Screws another 2 turns. Watch is still at +60 seconds a day. When I get home I will add timing washers to the meantime screws at the arms of the balance and get the darn thing timed.


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[nickelsilver]

I am being very careful. The watch has a 550 deg swing, amazing amplitude (270). So after 2 days the watch stopped. The non-quarter screw that I accidentally turned, thinking it was a timing screw as well, turned out on it’s own and ended up touching the balance cock. So I tightened the screw and it’s brother and turned the Meantime Screws another 2 turns. Watch is still at +60 seconds a day. When I get home I will add timing washers to the meantime screws at the arms of the balance and get the darn thing timed.


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No, washers only go on the normal screws, and get tightened down.

[jdrichard]

No, washers only go on the normal screws, and get tightened down.

So with the quarter screws for example?

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[nickelsilver]

Quarter screw and meantime screw means the same thing, I think the Brits say "quarter" more where Yanks say meantime. Some watches have 4, at 90 degree spacing (thus "quarter screw"), some just 2. When there are just 2 they are typically at the arms like in your watch. They are just for getting the balance close to a general (mean) time, with the regulator in the middle of its course. It's very much discouraged to use them for correcting poise error, although you can if it's just a small adjustment.

 

So you have two meantime or quarter screws, the rest are just balance screws. The meantime screws will always have a longer thread, and show some resistance to turning even when not screwed down- they will in fact generally not be screwed right down to the rim. The regular balance screws will always be a free fit on the thread, and always need to be screwed down tight. Timing washers are used on these screws if needed.

 

Balance screw holders are very nice to have, really essential for small balance screws, when dealing with adding washers. They are essentially little pinvices with sized tips, Bergeon sells them.

[jdrichard]

Quarter screw and meantime screw means the same thing, I think the Brits say "quarter" more where Yanks say meantime. Some watches have 4, at 90 degree spacing (thus "quarter screw"), some just 2. When there are just 2 they are typically at the arms like in your watch. They are just for getting the balance close to a general (mean) time, with the regulator in the middle of its course. It's very much discouraged to use them for correcting poise error, although you can if it's just a small adjustment.
 
So you have two meantime or quarter screws, the rest are just balance screws. The meantime screws will always have a longer thread, and show some resistance to turning even when not screwed down- they will in fact generally not be screwed right down to the rim. The regular balance screws will always be a free fit on the thread, and always need to be screwed down tight. Timing washers are used on these screws if needed.
 
Balance screw holders are very nice to have, really essential for small balance screws, when dealing with adding washers. They are essentially little pinvices with sized tips, Bergeon sells them.

So the timing washers would be placed on the two opposing screws that are 90 deg from the balance arms. Is this correct? By the way, thanks for the advice. And is there a book that explains the placement of timing screws . I do have the tools needed to work with the balance screws:)


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[nickelsilver]

You can put the timing washers on any two opposing screws, except meantime screws. Almost any watchmaking text should cover it, I'm sure Gazeley Decarle Fried and others go into it.

[vinn3]

17 minutes ago, jdrichard said:

So the timing washers would be placed on the two opposing screws that are 90 deg from the balance arms. Is this correct? By the way, thanks for the advice. And is there a book that explains the placement of timing screws . I do have the tools needed to work with the balance screws:)


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      do you a screw driver that will hold that little "cheese head" screw?     vin

[jdrichard]

      do you a screw driver that will hold that little "cheese head" screw?     vin

I have all the tools...trust me:)


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[jdrichard]

Luck, all luck. There is a story but these were unexpected

[vinn3]

id like to know what kind of small size screw driver is available.  im shure you have more watch tools than i     vin

[jdrichard]

id like to know what kind of small size screw driver is available.  im shure you have more watch tools than i     vin

Perhaps. Just got this tool


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[nickelsilver]

There are much more elaborate sets of timing washers, for a given size of watch there are usually 3-6 different washers possible. You can see the carton boxes are marked on the lid, the wooden Bergeon set inside, the Bergeon gives the watch size and hole size in the washer. Of course there can be balances with different inertia in a given ligne size so the "seconds per day" is an approximation.

 

I'm sure with your set you'll find some that get your watch on track.

[KarlvonKoln]

I know this is an old thread, but I wanted to remark that I am glad I found it.  I have a 1925 Waltham grade #210 which is running very fast, but a steady and consistent gain of 48 minutes per day.

Originally it was not running well because it had a cracked upper cap jewel and an upper pivot that had a bit nipped off the top.  I replaced the jewel and got a like-new balance complete, and poised it.

I made sure to get it in beat.  And it ran super fast, beyond regulating.  I examined the hairspring, and it wasn't touching or bumping anything, and coils were evenly spaced and breathing well. Still, I cleaned the balance and demagnetized everything.  Still too fast.  I adjusted the meantime screws, as explained in this post, and saw some minor reduction, but I think I will also need to add timing washers. I have a few that are the correct size.  The mainspring looks to be original but I think I will measure it again just in case.

Otherwise, it runs so smooth and so well.  Just hoping I can reign her in.

[KarlvonKoln]

Addendum: the picture of the movement is an earlier one.  Currently, the movement is the cleanest it has ever been and the regulator is all the way to the slow side.

This was what we Americans would label a "barn find", a ratty-looking but easily restorable piece going for cheap.  I paid $20 US.

[JohnR725]

On 9/5/2021 at 8:18 AM, KarlvonKoln said:

I know this is an old thread, but I wanted to remark that I am glad I found it.  I have a 1925 Waltham grade #210 which is running very fast, but a steady and consistent gain of 48 minutes per day.

one of the problems with finding a discussion like this is that I perceive each watch to be a unique problem and you really should post your own question.

On 9/5/2021 at 8:18 AM, KarlvonKoln said:

like-new balance complete, and poised it.

a problem with a like new balance complete is we do not know its history? Did somebody mix-and-match a balance wheel from one watch with the hairspring from another visually they look right but are they right?

Then before you poised did you true the balance wheel? In other words is the balance wheel perfectly round? The reason I ask is bimetallic balance wheels are easy to bend the arms in and if the arms are bent in by just the tiniest amount the watch runs fast. So before you can poise you do have to make sure the balance wheel is round.

typically in a discussion groups like this if somebody had a watch now running superfast in particular American pocket watch I would tell them to look at their balance screws. A lot of times one of the screws will fall out and then you run insanely fast. But as you did the poising that wouldn't be an issue.

then timing washers are not to be used for what you're thinking of using them for. Notice if you look at the images up above the rated as minutes per 24 hours. Also you're only supposed to have one washer under a screw so if you do the math you need a heck of a lot of washers and I doubt you have enough screws.

you'll notice I attached some images and a PDF. One of the images shows Waltham timing or poising screws. As it is possible to change the hairspring the only way he could bring the watch into time would be would have to build the change the screws. So typically any time hairsprings can be changed there are associated screws to go with it. You're running way too fast for any normal method of slowing it down you need heavier screws. Fortunately as you put a balance complete on you have an old balance wheel but you're not using so you can see if you can find suitable screws there. One of things you want to look for is if somebody got insane with undercutting the screw heads when they were doing that poising just putting screws on that haven't been undercut will help.

On 9/5/2021 at 8:18 AM, KarlvonKoln said:

The mainspring looks to be original but I think I will measure it again just in case.

then the mainspring is not the source of the timing problem unless it's dramatically wrong. And I would give it was super super strong. But if it is the original mainspring and it looks set it will definitely be a running issue problem you won't get 24 hours a running time.

 

 

hamilton_tech_note_on_regulation.pdf

[KarlvonKoln]

@JohnR725 thank you for the wealth of information on this.  I originally posted here in an effort to see if my problem was common enough to already have an answer.  Most do.  I do try to search the forum first before posting something which may be a rehash.  But this time, I must agree with you: to get answers specific to this watch, I will have to draft its own post soon.

To answer an earlier question, I did both true and poise.  It seems quite true and balanced.  BUT...I did not think to look for undercut screws at the time.  I will be doing that.  And I will spend some time reading over what you sent, and contemplating the physics of what's going on.  Thank you again sir.