How much time gain is normal in 24 hours?

[haakon59]

Wouldn't the normal gain be 24 hours?

[Earl Camembert]

My 1968 DD does not have a hacking mechanism so it is difficult to set it to the exact time. Before it fell 7 feet onto a tile floor it was about 4 seconds a day slow; it is now 14 seconds slow but that is consistent.

[slevin kelevra]

Originally Posted by Highhorology

Whew, I guess I'll weigh in on this one. When I worked at Rolex we timed the watches in 5 positions crown down, crown left, crown up, dial up and dial down. It can be timed in crown right but most people don't walk around with their hand up over their shoulder all the time.

Having said that there is what is called isochronism. Isochronism means that the rate is the same between the short arcs and long arcs of the balance wheel. O.K. so if your balance wheel is isochronous then it won't gain or loose regardless of the amount of power reserve right? Wrong! The fact is that the power transmission that takes place in the escapement is a net loss due to that little thing called friction.

So then the balance wheel is designed to be a little fast to make up for the loss in friction, and slightly faster in the short arcs than the long arcs. What does this mean to you the guy wearing the watch? It means that even a properly adjusted chronometer will tend to gain a little if not kept wound at least above half wind. Six hours of normal movement per day should do it, if not and if it is important to you then you should consider either winding your watch once a day or getting a winder to put it on at night.

The hairsprings of most Rolex are what is called the over coil or Breguet style which is designed to compensate the errors caused by the pining point on the hairspring collet. In addition to that the hairpring is pinned to the poised collet in such a way as to enable a watch maker to adjust any loss in the oscillating mechanism to one particular position, namely the pendant right position.

All this being said, yes your Rolex watch can certainly run at +-0 sec. a day +3-5 sec. a day is acceptable for a warrantied repair or a new watch. I like to see 0 to +2 sec. a day. Yeah their pretty accurate.

There should never be a loss unless a major impact puts the watch way out of beat, or if you sleep on the bathroom floor and get up to go!

Very interesting read mate.

Id like to add one thing though! I wear my 1 month old sub ND for at least 6 hours each day and leave it face up at night and it consistently looses half a second a day when timed over a 10 day period.

You have stated that a watch will always gain time. I find that not to be the case with mine. Or I suppose one argument could be that I could leave it in a different position overnight but then again im pretty happy with the accuracy so there isnt much point.

[Highhorology]

Originally Posted by slevin kelevra

Very interesting read mate.

Id like to add one thing though! I wear my 1 month old sub ND for at least 6 hours each day and leave it face up at night and it consistently looses half a second a day when timed over a 10 day period.

You have stated that a watch will always gain time. I find that not to be the case with mine. Or I suppose one argument could be that I could leave it in a different position overnight but then again im pretty happy with the accuracy so there isnt much point.

I guess I should rephrase that a properly maintained and adjusted Rolex should never loose time even if the power reserve drops below 1/2 wind. I would expect that your watch will slowly begin to gain a little as time goes on.

[slevin kelevra]