[jmj]

i know both are factors, or course. but do certain movements, in general, run slow or fast in specific positions? i started wondering this after my recent whining about my credor's accuracy. i did a little searching and found jayhawk's research into the positional accuracy of several of his watches. luckily, one of them was an 8L75 movement like mine!

so i used his findings as a basis for deciding how to place my watch when i wasn't wearing it, and it worked! by placing it face-down for the 3 or so hours i'm not wearing it every day, it actually began to gain a bit rather than losing.

i'm just wondering if all 8L75 movements would follow the same pattern, or did i just happen to get hold of one that had the same characteristics as his? i won't even pretend to understand all the factors at work here, but i'm sure there are some here who have theories or observations of their own.

 

[minidriver]

Remember that mechanical watches are both affected by positional variance (gravity) and temperature.

Most mechanical movements are unadjusted for position and temperature. Movements like the 7s26, 6r15, etc are example of calibers not adjusted for positioning.


This is why Seiko says... "Your watch accuracy is -15/+25 secs per day" but they don't guarantee the accuracy because it may vary according to position. Then there is variation from same caliber to the next.

More expensive mechanical movements like the 8l35, 9S family are adjusted in 6 positions in addition to temperature. Watches tend to gain time in colder weather and lose time in warmer climate conditions.


For instance, Grand Seikos come with a factory certificate of accuracy (Like a COSC certificate) showing the accuracy of the watch on each position... Crown up, down, face up or down. With those calibers, Seiko will guarantee their accuracy (Typically -5/+3 secs per day) regardless of the position or ambient temperature. This is why these watches cost upwards of $3,000.

The mechanical watch escapement, as good and reliable as it is, is 500 year old technology with the limitations noted above. This is why mechanical watches can never be as accurate as quartz counterparts.