Tobias "half seconds"

shinytickythings

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So, my big personal takaway from the NAWCC convention mart was I managed to find a Tobias "Half Seconds" watch.
This one is actually signed as such on the dial, which I though was cool, and the dust cover is signed "Made Expressly for Geo. W. Welsh N.Y.".


So . . . it's a 30 tooth escape wheel, rather than 15 that makes it do that?

001.jpg 003.jpg 004.jpg 005.jpg
 

gmorse

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Hi Steve,
So . . . it's a 30 tooth escape wheel, rather than 15 that makes it do that?
It doesn't look like a 30 tooth escape, just the usual 15 as far as I can see, but it does have a higher than usual pinion count, possibly 12. These slow-beat watches, (many of which were made to the designs of Thomas Yates of Preston), had unorthodox train counts. If you remove the dial it would be interesting to see any marks on the pillar plate.

Thirty tooth escape wheels were usually fitted to three-wheel trains, and if a seconds hand was included it was on the escape arbor and the seconds bit was calibrated only 1 to 15, because the hand rotated in 15 seconds.

Regards,

Graham
 
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shinytickythings

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Thank you, Graham!
I was so excited to find it I didn't even count the teeth before I posted this.
I haven't come across one of these before. I had read about them, but my memory was kind of foggy.
That's very informative and interesting, and I'm going to be more than happy to post some pictures from under the dial tomorrow and will also be sure and take a close look at the train.

All the best,
Steve
 

John Matthews

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It appears to me that the escape has 15 teeth and 14 leaves. Assuming the dial is original, and I can see no reason why it should not be, then the 4th, upon which the second hand is mounted, is rotating at 120 revolutions per hour. I think I am correct in assuming that the 4th would have between 50 and 60 teeth. If it has 56 teeth and I am correct that the escape has 14 leaves, then the escape would be rotating at 120*56/14 = 480 revolutions per hour and with an escape with 15 teeth that would give a 480*15*2 = 14,400 train. If the escape has 12 leaves and the 4th 60 teeth, then that would give 120*60/12 = 600 revs for the escape and 600*15*2 = 18000 train.

John
 
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gmorse

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Hi John,

I agree, but in order to arrive at 14,400 there must be larger tooth counts on the centre, (second), third and/or fourth wheels, because the third or fourth pinions can't have only four leaves, in fact they couldn't realistically have fewer than 6, which would still give higher engaging friction. Eight or more is the usual count on better quality work.

These train counts for Thomas Yates watches are from the article by Carrington and Kemp in AH December 1984:

Yates Train Counts.png
And these from Carrington's June 1975 article:
Yates Train Counts 2.png
These latter both constitute a 7200 train.

I think we must wait for Steve to count the train on his Tobias.

Regards,

Graham
 

shinytickythings

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It appears to me that the escape has 15 teeth and 14 leaves. Assuming the dial is original, and I can see no reason why it should not be, then the 4th, upon which the second hand is mounted, is rotating at 120 revolutions per hour. I think I am correct in assuming that the 4th would have between 50 and 60 teeth. If it has 56 teeth and I am correct that the escape has 14 leaves, then the escape would be rotating at 120*56/14 = 480 revolutions per hour and with an escape with 15 teeth that would give a 480*15*2 = 14,400 train. If the escape has 12 leaves and the 4th 60 teeth, then that would give 120*60/12 = 600 revs for the escape and 600*15*2 = 18000 train.

John
Hi John!

Thank you!
This is all fascinating.
I'm not sure how I conflated the 30 tooth escape wheel with the "half seconds".
But there were some with 30 tooth wheels, right? I didn't just dream I read about that, did I?

All this has me wondering, what was the purpose of the 30 tooth escape wheel, and
what was the purpose of a "Half Seconds"?

All the best,
Steve
 

gmorse

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Hi Steve,
But there were some with 30 tooth wheels, right? I didn't just dream I read about that, did I?
Yes, of course there were, it was a way of achieving a 14,400 train with only three wheels, without using impossibly large second and third wheels.

DSCF6605.JPG

This is from a rack lever, but could easily be from a detached lever.

Regards,

Graham
 
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shinytickythings

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Hi Steve,

Yes, of course there were, it was a way of achieving a 14,400 train with only three wheels, without using impossibly large second and third wheels.

Regards,

Graham
Thanks, Graham!
So, my memory isn't great, but at least my sanity is intact. lol
Just starting the day here so I have a few things to do first, but I'm looking forward to taking a closer look at it first thing when I get in the office.

Regards,
Steve
 

John Matthews

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If the second hand does make one revolution every 30 seconds and it is mounted on the 4th and if we agree that the escape has 15 teeth and 12 or 14 leaves - then none of the Carrington (and Kemp) examples are possible. In all those cases the 4th is rotating 60 times per hour - here we have 120 revolutions per hour. I agree that the teeth count would need to be higher and I found Liverpool examples, particularly those with three wheel trains, where second and third wheels had up to 90 teeth.

I use a spreadsheet to calculate train rates - here is the analysis of the Carrington examples and 3 possibilities for this movement. The last being the slowest beat I think is possible. Happy to be proved wrong.

1626870866428.png

John
 
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gmorse

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Hi John,

Looking back at some earlier records I have, there are indeed some three-wheel trains with a 90 tooth second wheel and a 96 tooth third wheel, so your figures do make sense. I think these higher tooth counts are approaching the practical limits for watches of this type and size.

Regards,

Graham
 

SKennedy

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Just thinking aloud that there would be some irony if this turned out to have a 16200 or 18000 (or other) train which would mean that the seconds hand doesn't actually land on the half second marks! 14400 would make the most sense for the specific sales point of the dial layout.
I think that escape pinion is 12.
 

John Matthews

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Seth - with 12 leaves on the escape, there would have to be 48 teeth on the 4th to give a 14,400 train ...

1626884737781.png

The smallest number of teeth on a 4th wheel that I have is 50, which I have only recorded on Yates's slow beat examples, most single rollers and Massey's are have 54 or more - but I only have a small sample - Graham and yourself will probably have more data.

John
 

SKennedy

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That previous thread linked to by John Pavlik andP/L would appear to confirm a 14400 train. The tooth count on the 4th wheel certainly doesn't look particularly high, so it could well be 48.
 
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Ethan Lipsig

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Having zero watchmaking skills, I understand relatively little of the discussions in this thread. I have two questions: What does a "half-second" watch do? Is my M.J. Tobias rack lever a "half-second" watch. It has a 15-second subseconds dial, and a 30-tooth escape wheel. From a quick glance, the second hand appears to rotate forward in three short steps per second.

IMG_8958_edited.JPG IMG_1698.jpg
 
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gmorse

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Hi Ethan,
I have two questions: What does a "half-second" watch do? Is my M.J. Tobias rack lever a "half-second" watch. It has a 15-second subseconds dial, and a 30-tooth escape wheel. From a quick glance, the second hand appears to rotate forward in three short steps per second.
The 'half-second' part really refers to the seconds bit on the dial only being calibrated up to 30 instead of the more usual 60 seconds. Because the seconds hand is mounted in the extended 4th wheel arbor, and the minute hand is on the centre arbor, (which must therefore take one hour to make a full rotation), we can make inferences on some of the tooth and pinion counts in the train, and also that the number of beats per hour is 14,400, or 4 per second.

Your rack lever is probably also beating at 14,400, and has a 30 tooth escape wheel, so what you can see is the seconds hand making four steps in a second; it's hard to see the four separate steps with the naked eye, even with magnification. The watch wouldn't be regarded as a 'half-second'.

Regards,

Graham
 

shinytickythings

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Ok.
I appreciate all of the very interesting discussion. It's is tempting to just let it roll to see how much more I can learn before the big reveal.
Are you ready?
Drum roll please . . .

Standard single roller escapement.

Fusee. 70 teeth
2nd. 72 teeth, 10 leaves
3rd. 60 teeth, 6 leaves
4th. 40 teeth, 6 leaves
Escape. 15 teeth, 10 leaves.

iinm, 14,400 bph.

Thank you all so much for you insight.
Anything further is of course, also greatly appreciated.

Regards, Steve

018.jpg 022.jpg 026.jpg 030.jpg
 
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John Matthews

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The 'half-second' part really refers to the seconds bit on the dial only being calibrated up to 30 instead of the more usual 60 seconds.
Just to clarify this is different from the term 'beating half seconds' as applied to slow beat movements, typified by those made by Yates. In those watches the balance 'beats' twice per second i.e. 2*60*60 =7200 beats per hour. The term 'slow' being applied to beats <14400 bph.

John

Edit - Steve were there any maker's marks on the pillar plate or the inside of the cap?
 
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Ethan Lipsig

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Graham, you say that a Tobias "half-second" watch has a subseconds dial that only shows 30 seconds, i.e., the second hand rotates once every 30 second. You say that my Tobias isn't a half-second watch because its subseconds dial only shows 15 seconds and the second hand rotates once every 15 seconds. That would make sense if my watch were a "quarter-second" watch. Is it?
"
 

gmorse

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Hi Ethan,
You say that my Tobias isn't a half-second watch because its subseconds dial only shows 15 seconds and the second hand rotates once every 15 seconds. That would make sense if my watch were a "quarter-second" watch. Is it?
I suppose you could call it that, but any watch beating at 14,400 bph will make four steps per second, and these movements with 30 tooth escape wheels are usually identified by this characteristic and aren't called anything else specific as far as I know. They don't usually have a seconds bit, so their nature is hidden unless you look into the edge of the movement.

Regards,

Graham
 
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shinytickythings

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Just to clarify this is different from the term 'beating half seconds' as applied to slow beat movements, typified by those made by Yates. In those watches the balance 'beats' twice per second i.e. 2*60*60 =7200 beats per hour. The term 'slow' being applied to beats <14400 bph.

John

Edit - Steve were there any maker's marks on the pillar plate or the inside of the cap?
Nothing notable that means much to me, but took some pics because I know those are areas of interest.

004_2.jpg 005_2.jpg 009.jpg
 

shinytickythings

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I'm still not entirely clear on the purpose of the "Half Seconds" watch.

And, looking at the link to John Pavlik's thread, I notice it is written up on the receipt as a chronometer.
. . . where to begin?

How abut that 40 tooth 4th wheel, John? Any thoughts on that?

I really haven't even begun to think through all of the questions I have about this.

Sadly, I discovered it has a broken mainspring. I don't see any other evident damage and it did tick quite well with a slight reverse pressure to the fusee, but I did notice that the potence is lifting or bent up off the plate a bit(?) Not sure what's going on there. That needs further investigation. But, it's mostly academic. I'll probably just put it back together and shelve it in my collection seeing as it's an orphan.

All the best,
Steve

024.jpg 034.jpg
 

John Matthews

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Steve - sorry to hear that the movement has problems.

My personal view is that having a subsidiary marked 0-30 and a second hand making two rotations per minute is more about producing a watch that was different, in an attempt to achieve commercial advantage. I cannot think of any practical reason for such a configuration - but someone may. The use of the term 'chronometer' I view similarly, which speaks to an attempt to convince of accurate time-keeping.

Unfortunately, being a collector rather than a watch repairer, I am limited by inspection of my own collection and when I am fortunate to view photographs and descriptions of movements that have been disassembled. So in my limited experience I am surprised to see a 4th wheel with only 40 teeth - it is the smallest number of I have recorded. Graham and Seth - are the better placed to judge whether it is unusual. They may also be able to add comment on the number of leaves on the pinions.

I can help a little with the cap. The stamp 'F' is known to me and although I cannot be certain of the name of the cap maker who used this mark, there was a family of cap makers in Coventry who are candidates. The mark is found on Liverpool finished watches ~1840.There is a description, but unfortunately no photograph of the cap, here. I infer that that your well fitted cap was made in England, possibly in Coventry, but the watch was probably finished in Liverpool. I believe this date corresponds well with the age of this movement. A similar Tobias watch #31959 is known in a 1839/40 hallmarked case. In my view it is possible that this is an example of a movement that was exported and then cased in America. The dedication on the cap, is similar to other examples I have recorded, and it is an open question as to whether the cap was engraved in England, having been specified on the order, or whether it was done after arrival in America.

Steve - thanks for starting this well illustrated thread - it has generated some informative discussion.

John
 
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gmorse

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Hi Steve,

The pictures are good but there isn't a frame maker's mark on the pillar plate, which is what we were hoping to see. John may have some idea about the 'F'' in the cap.

How abut that 40 tooth 4th wheel, John? Any thoughts on that?
It's unusually small, but then this is an unusual train.

...but I did notice that the potence is lifting or bent up off the plate a bit(?) Not sure what's going on there. That needs further investigation.
Can you tell if its screw is in place? These are pretty hard to bend unless extreme force is used.

Regards,

Graham
 
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gmorse

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Hi John,
They may also be able to add comment on the number of leaves on the pinions.
Six leaves on a cycloidal pinion is really the lower limit for practical applications, and it does involve action well before the line of centres which results in engaging friction, an undesirable condition. This is reduced in pinions of eight and is eliminated in pinions of ten and twelve, which is why higher count pinions are usually fitted in top-end movements. I think in this particular example the escape pinion has a higher count mostly for reasons of mathematics rather than frictional considerations, because the 3rd and 4th wheels have pinions of only 6, although the pinion of 10 on the escape will have a larger effect than those of 6 on the 3rd and 4th wheels.

Regards,

Graham
 

shinytickythings

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Steve - sorry to hear that the movement has problems.

My personal view is that having a subsidiary marked 0-30 and a second hand making two rotations per minute is more about producing a watch that was different, in an attempt to achieve commercial advantage. I cannot think of any practical reason for such a configuration - but someone may. The use of the term 'chronometer' I view similarly, which speaks to an attempt to convince of accurate time-keeping.
That is pretty much what I was thinking. "It has to be "marketing", right?"
The "Chronometer" part seems pretty obvious. I mean, it's a nice quality watch and all, but . . .
Though, I still feel like there is something I'm missing about the "Half Seconds" bit.
Some implication to the marketing gimmick that I'm not grasping, maybe.

Unfortunately, being a collector rather than a watch repairer, I am limited by inspection of my own collection and when I am fortunate to view photographs and descriptions of movements that have been disassembled. So in my limited experience I am surprised to see a 4th wheel with only 40 teeth - it is the smallest number of I have recorded. Graham and Seth - are the better placed to judge whether it is unusual. They may also be able to add comment on the number of leaves on the pinions.

I can help a little with the cap. The stamp 'F' is known to me and although I cannot be certain of the name of the cap maker who used this mark, there was a family of cap makers in Coventry who are candidates. The mark is found on Liverpool finished watches ~1840.There is a description, but unfortunately no photograph of the cap, here. I infer that that your well fitted cap was made in England, possibly in Coventry, but the watch was probably finished in Liverpool. I believe this date corresponds well with the age of this movement. A similar Tobias watch #31959 is known in a 1839/40 hallmarked case. In my view it is possible that this is an example of a movement that was exported and then cased in America. The dedication on the cap, is similar to other examples I have recorded, and it is an open question as to whether the cap was engraved in England, having been specified on the order, or whether it was done after arrival in America.

Steve - thanks for starting this well illustrated thread - it has generated some informative discussion.

John
All fascinating information for me.
Thank you, John!
 

shinytickythings

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Hi Steve,

The pictures are good but there isn't a frame maker's mark on the pillar plate, which is what we were hoping to see. John may have some idea about the 'F'' in the cap.
Yeah. I'm way more disappointed about there being no frame maker's marks than I am about the mainspring being broken. :(
It's unusually small, but then this is an unusual train.
Sure is to me!
I'm still trying to digest what you've shared about the mechanics of the pinion count and apply it to all of the what/how going on with this watch.
Did the "Half Seconds" bit work as a marketing gimmick because it made the watch look like it was running faster and thus the implication was it was a higher quality watch, when in fact they were just using up old stock of the 14,400 train watches? They were producing 18,000 bph watches by this point, weren't they?
Can you tell if its screw is in place? These are pretty hard to bend unless extreme force is used.

Regards,

Graham
I was going to say you won't believe this, but actually, you probably will. lol
It is indeed screwed down. And, there's 3 steady pins.
As soon as I went back to take a second look at it this morning after I read this, it's fine. Nice and flat and flush.
And, there doesn't seem to be anything removed during the disassembly that would have been pushing on it or causing that. I'm mystified.
I guess I'll see what happens as I put it back together.

Regards,
Steve

001.jpg 002.jpg
 
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shinytickythings

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Ok. That didn't take long to sort.
It's just the screw from the barrel bridge.
It's countersunk "itself" down into the plate until now it is protruding underneath.

Edit:
I take that back, too.
Not burrowed into the plate.
One screw is longer than the other and they were mixed up.
 
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gmorse

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Hi Steve,
One screw is longer than the other and they were mixed up.
Ah, that's why these screws and their holes were often marked with one or two 'pips' to ensure they went back in the right place. I don't know why the maker made the potence foot so large, it doesn't need to be. It's not as if it has to cope with heavy loading.

Regards,

Graham
 
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SKennedy

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That is pretty much what I was thinking. "It has to be "marketing", right?"
The "Chronometer" part seems pretty obvious. I mean, it's a nice quality watch and all, but . . .
Though, I still feel like there is something I'm missing about the "Half Seconds" bit.
Some implication to the marketing gimmick that I'm not grasping, maybe.
My take: Most English lever watches have either 16200 or 18000 trains (some have oddballs in between). Since that means a beat of 4 1/2 or 5 per second, a seconds hand would never fall exactly on a half seconds mark. Someone/Tobias has decided it would be an interesting niche to market a watch that shows quite clearly 1/2 second intervals but with a standard train layout and normal sub-second dial rather than centre seconds. To have the hand point to the half seconds its going to have to have a 14400 (4 beats per second) train.

But, it would be barely readable to divide a normal '60' sub seconds dial to show half seconds. So they've altered the train count to give a '30' seconds dial, with the halves clearly marked. I think this is the real sales point. The readability of the '1/2 second' dial. Their customer can now start/stop their watch to time events to the nearest half second - or actually quarter second for the in-between beats - which is quite clearly displayed.
 

shinytickythings

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Well, I had determined not to service it or anything on account of it having a broken mainspring.
But, I did clean it up a little and gave it some love.
Now it's back up and "running".
Has a pretty good tick really even with just minimal wind it will take before the mainspring slips.
 

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