Time reference

[Slick]

I've had my "new to me" Rollex Sub for about a week now and I believe it is running fast, on the order of 20-30 seconds per day. I've not kept good notes or anything . . . yet, but I do want to be sure that I'm comparing the watch to a good reference.

I've been using: http://tycho.usno.navy.mil/simpletime.html

My question is, is this a good reference point? If not, is there another that I should consider?

[padi56]

Originally Posted by Slick

I've had my "new to me" Rollex Sub for about a week now and I believe it is running fast, on the order of 20-30 seconds per day. I've not kept good notes or anything . . . yet, but I do want to be sure that I'm comparing the watch to a good reference.

I've been using: http://tycho.usno.navy.mil/simpletime.html

My question is, is this a good reference point? If not, is there another that I should consider?

First give your watch a full manual wind say 40 full crown turns clockwise .Then set time with any reliable time source a quartz watch will do or the one you selected wear as normal.Check daily with the same setting time source for 5 days then average out your loss or gain.I would be very surprised if your watch is gaining 20-30 seconds a day.If it checks out that watch is gaining have it regulated but do a accurate test before you get the back off.

[Slick]

I just checked it after one hour (I know, not very scientific) but it is a beat over 1 second faster than the US Navy time site. That would put it at 24 seconds or so for a day, just about what my non-scientific guesstimate was.

I've done the full manual wind. I've set it on its side with the crown up at night and that seems to slow it down a bit over the 24 hour period. I'll keep making notes for another week or so before I do anything rash.

[padi56]

Originally Posted by Slick

I just checked it after one hour (I know, not very scientific) but it is a beat over 1 second faster than the US Navy time site. That would put it at 24 seconds or so for a day, just about what my non-scientific guesstimate was.

I've done the full manual wind. I've set it on its side with the crown up at night and that seems to slow it down a bit over the 24 hour period. I'll keep making notes for another week or so before I do anything rash.

Forget about checking your watch every hour there will always be tiny daily variations,thats why they are tested in five different positions.Just try and check it daily at the some time with the setting time source.Then if it is gaining have it regulated, its also possible you watch could be magnetised.
But then watches that are magnetised tend to run very very erratic speed up slow down or come to a complete stop and refuse to start.But regulation or if needed de-magnification both very very simple proceeder's

[Tools]

I think that you're working in the right direction..

A simple regulation is pretty cheap. If the watch is 10 years or so without a clean and oil (service), then that is the expensive route, but it will be nearly like a new one..