Why Is A Winder At 3 O’clock
The Technical Theory

The Tradition Of Open-Face And Hunter Calibers

Posted by Walt Odets on October 19, 1997 at 16:30:31:

In Reply to: The crown is always at 3 o’clock, why?

posted by Lars Lange on October 18, 1997 at 23:04:47:

The term “caliber” signifies the way in which the movement parts -train, bridges, etc.- are arranged. Traditionally, there are two types of calibers, open-face and hunter.

In the former, in which the dial is protected only by a glass, the winding stem, center wheel and fourth wheel (which carries the small seconds hand) are set in a straight line. In the hunter caliber, with a metal cover over the crystal, the winding stem, center and fourth wheels are traditionally set at right angles. This places the crown at 3:00 o’clock and the small second dial at 6:00 o’clock. The hunter caliber is the predecessor of the traditional wristwatch. A caliber could be designed to put the stem wherever it was desired.

Patek (350 automatics), JLC (Future Matic) and others have put the crown on the back of the watch. In the 350 automatics the winding weight ran around the perimeter of the movement, and a stem would have obstructed it. In the JLC Futurematics, the back location of the crown allowed a larger balance wheel and also emphasized the self-winding nature of the watch for marketing purposes.

In the case of directly driven center second movements (as opposed to indirectly driven center seconds or “subsidiary” seconds at 6:00 o’clock), the center wheel is taken out of the center position anyway, so the crown position is completely arbitrary. Almost everything on a wristwatch is traditional and, in that sense, arbitrary. “Regulator” dials, single hand dials, and jumps hours are variations on the most basic tradition in watches, two centrally mounted hands.

Posted by Lars Lange on October 19, 1997 at 17:40:59:

In Reply to: The tradition of open-face and hunter calibers…

posted by Walt Odets on October 19, 1997 at 16:30:31:

Thanx Walt

So the 3 o’clock position of the crown is a combination of both logical and technical considerations. You say that the modern wrist watch is the “result” of the hunter movement. Does that mean that all the well know center second movements (ETA 2824, 2892, JLC 889 and so on) has indirectly driven seconds and before “modifications” has their seconds at 6 o’clock? Is the Zenith Elite movement an open-face construction? In the basic version it has the seconds at 9 o’clock.


Partial answer…

Posted by Walt Odets on October 20, 1997 at 3:55:44:

In Reply to: Questions on open-face and hunter calibers…

posted by Lars Lange on October 19, 1997 at 17:40:59:

The position of the winding/hand setting stem (and thus the crown) was, at one time, largely a logical and technical consideration. In the modern watch it is more an issue of tradition. The ETA and JLC movements you mention all have direct (not indirect) seconds, which means that they have indirect (not direct) minutes.

In such movements, the “center” wheel (which drives the minute hand) is moved out of the center of the movement and the seconds wheel (which is the fourth wheel, located in the train right before the escape wheel) is in the center of the movement. “Small seconds” (on a small subsidiary dial) are usually driven directly off the fourth wheel pivot (this is a kind of “direct seconds” because the wheel is in the power flow of the wheel train), but small seconds could be put anywhere by being indirectly driven (outside of the power flow), though I’m not sure I’ve ever seen this done. This could be the case with the Zenith movement (indirect subsidiary seconds), but it is probably a true “open face caliber” construction with the stem, center wheel and fourth wheel in line. I do not actually know the movement. People forget that you can use a movement in any position of rotation by simply rotating the dial relative to the movement (to keep 12:00 o’clock at the top). This would allow you to put the crown anywhere you wanted with a center seconds watch. With a subsidiary seconds watch, it would move the seconds dial to an unusual position.

If you look at the Zenith movement, see where the fourth wheel is (it will be rotating once per minute, by no coincidence, and driving the escape wheel pinion). Oris also has a watch with seconds at 9:00 o’clock, and to me this is done to speak to watchmakers about the layout of the caliber (stem, center wheel, fourth wheel in line). But I have an idea (I’m not sure) that Oris is faking this by driving the seconds indirectly.

If you look at a Patek Ref. 5000 with small seconds at 4:30, this is because that is where the fourth wheel is located in the movement. Here the stem, center wheel and fourth wheel are at about 45 degrees to each other, and the layout of the dial is “technically honest.”

Zenith, incidentally, invented the layout of most modern calibers in 1948 when they created the directly driven center seconds watch and moved the “center” (minute) wheel out of center. This arrangement not only allowed a directly driven center seconds (which usually moves more smoothly than an indirectly driven center seconds) it allowed room for a larger spring barrel and larger balance. This layout was almost universally copied by others. In this movement, the minute (“center”) wheel ended up at about 8:00 o’clock. Could this all be any more confusing?

An addendum (believe it or not)…

Posted by Walt Odets on October 20, 1997 at 4:02:20:

In Reply to: Partial answer…

posted by Walt Odets on October 20, 1997 at 3:55:44:

I failed to answer part of Lange’s question. No, the ETA and JLC movements are “Zenith style” direct center seconds calibers with the fourth wheel mounted in the center of the movement. The traditional open-face and hunter calibers are both subsidiary seconds movements. That is why, with directly driven center seconds, the position of the crown at 3:00 o’clock is simply tradition and, in that sense, arbitrary (barring other considerations). And, of course, traditional calibers do not account for automatic winding mechanisms and the demands they might place on crown position (although they are usually designed with a 3:00 o’clock crown in mind).