The basic rule of "position accuracy" is to get the Balance wheel perfectly poised (balanced), the pivots clean, mirror smooth, and free spinning in the movement (without the hairspring) in all positions and diagonal angles (18 in all).

THEN! you MIGHT have a chance to adjust the watch to remain accurate in all 6 positions!

In the balance wheel there is still ONE VERY LARGE "DEVIANT" EFFECT!, the "hairspring"!

IF the Hairspring is FLAT, it will never show RR accuracy reliably in 4 positions let alone 6. (Side note, if you have a Flat Hairspring movement that is 6 position accurate in 6 positions to 30 sec a week SELL IT NOW . . . And retire rich.)

The "invention" that helped reduce hairspring dynamics effects on the position accuracy equation was made by Mr. Breguet and is named after him. It is a series of clever bends and angles of the hairspring from the outermost coil to the stud which compensate the offsetting effects from torques of the hairspring's coiling and uncoiling during operation. (Picture below)

WITH a Breguet hairspring adjustments to cancel deviations in time accuracy due to gravity can be done by a practiced watchmaker. (Method described in Bulova Watch School book).

These adjustments generally disappear when the watch is disassembled for cleaning. So when you have a BREGUET Hairspring equipped watch that keeps good time face up and face down, you have good pivots, when it also keeps good time pendant up and pendant down, the balance wheel is generally well balanced. When it keeps good time in all 6 positions, it has been "fully adjusted which included the tweaks where necessary to cancel gravity effects on the hairspring.

The little devil!

A new challenge, checking the time keeping accuracy of a watch in each of the six positions.

Then I will really know how good a timekeeper my watch really is.

Thanks Dave.

quote:

These adjustments generally disappear when the watch is disassembled for cleaning.

Dave, this is something I've wondered about. When you perform a routine cleaning and servicing on a RR grade "adjusted" watch, is it necessary to go through the entire process of re-adjusting the watch , including hairspring, as was presumably done at the factory, in order for the watch to still be considered "adjusted"?

Dennis

Older watches often change dramatically because as the Hairspring ages, hairspring hardness also changes affecting both position adjustments and temperature adjustments.

Because disassembly and service requires handling the balance wheel and hairspring assembly, the watch must be re-tested in all positions and re adjusted where necessary.

An interesting topic David.If I was paid by the hour for the time I have spent adjusting hairsprings trying to get an accurate time piece I would be a rich man.....
Regards, John