two-hour minute hand

[Tommy in Scotland]

I know this is mainly to do with clocks, not watches, but the old Chinese clocks sometimes had a 2-hour minute hand and a 24-hour hour hand, to be used with a combination of twelve Chinese characters and two sets of twelve Roman numerals. Some good eighteenth century astronomical clocks also had the two hour minute hand and double-twelve hour Roman dials. Is there any evidence of this being done on watches? The S. Kato clock here shows 11:05PM! And it's another Tommy dial... the original was so worn and flaked some parts of it were just bare metal.

Tommy.

[francis 24/24]

Any tip of the minute can be used for the minute reading. By the way it seems
to be the only 24-hour watch ever made by Seiko. With a few model variation as
shown in the gallery of Andre (aai)'s site :

http://www.24hourwatch.info/

Cheers,

Francis

[Tommy in Scotland]

Hmm... different, but I'd be tempted to put ordinary hands on it!

[francis 24/24]

Are hands specific to a model or a brand ? This does no seem an easy job,
picking up hands you like and which should also fit. How do you know ?
I believe not every watchmaker can do this match. May be Dennis who
had this done on its Universal Geneve could elaborate ?

Well, thanks Tommy for having looked at this very unusual watch,

Francis

[Tommy in Scotland]

Well I'm no expert Francis but I suspect the only two vital criteria are: the centre fitting (specific to each movement) and the length. Every example of a particular movement is likely to take the same centre fitting. However, when working with clocks, I have been amazed to find that centres were sometimes changed on a particular movement during the production run. I've never changed hands on a watch. I'd be tempted to change the hands on some Raketas, as they often make them with hands which are way too short for the dial. This is offputting especially when you have all 24 hours on a dial.

Tommy.

[francis 24/24]

but you are for sure an expert in clocks :-! ! And you have a very nice
collection of 24-hour clocks !
Congratulations,

Francis

[Tommy in Scotland]

Hi Francis,
well thanks! But there's no such thing as an expert in clocks! Or so I'm told... Apart from the Chinese and Russian ship's clocks I also have a Kienzle 8 day travel alarm with an extra hour hand, a feature I now know to be a GMT. The alarm hand is used in alignment with the extra hour hand. I bought this clock from a seller in Germany about four years ago. I was lucky to find it as I had no idea such things existed. It dates back to the late 1950s or early 1960s and would never have been sold new in the UK, people over here don't generally think the right way to appreciate the complexities and logic of GMT dials. I've never seen another one since. I suspect it was a rare model.

Tommy.

[francis 24/24]

here it is :
http://jorune.net/%7Efmx/Montres/Photos/seikosmall.jpg

[Tommy in Scotland]

Yes it's nice indeed, and you take better photos than me, drat it...

Tommy.

[francis 24/24]

24-hour dial : it's obvious. But the 2-hour minute hand :-S
Do you know the reason ? I have a hypothesis : would it be easier to build
based on an ordinary 12-hour movement ?
And by the way why only 12 chinese numbers (and not 24 ) ?

Cheers,

Francis

[Tommy in Scotland]

Well, it would appear there are 12 Chinese hours in a day, so everything is twice as long... 120 mins for the minute hand to turn, 24 hours for the hour hand. And with the watch, I suppose it's easier (and cheaper) to set one of the internal transistors to count two seconds (instead of one) than it is to design and fit 24:1 gearing for the hour hand. Again just my theory.
Thomas Tompion built two identical clocks for the Royal Greenwich Observatory about 1700. They were standard longcase clock movements but made to run for a year, and they each had a two second pendulum... so the entire mechanism was geared to run at half speed... the seconds hand turned in 2 minutes, the minute hand turned in 2 hours. So you might expect the hour hand turned in 24 hours? Nope. He geared them with a 6:1 hour hand so they had twelve hour dials with double-60 minute minute hands! So if it looked like quarter past four it was actually half past! It wouldn't have confused anyone in those days as minute hands were still an innovation and most people didn't use them anyway!

Tommy.

[francis 24/24]

nt

[Tommy in Scotland]

Sorry I don't know what nt means... thanks anyway!

Tommy.

[francis 24/24]

no text in the body of the post, every thing is in the title.
Cheers,

Francis

[Tommy in Scotland]

Ah.... OK!

Tommy.