Datejust 1601/34 - Winding, Power Reserve, Time Test

[thejo]

Hi all — I finally joined the forum, though I’ve explored lots of the threads!

I was gifted an OP Datejust 1601/34 about 15 years ago (serial number dates to 1966 based on the Bob’s Watches table and 1060 based on other online tables). I had the head serviced by RSC in 2016. Unfortunately, I have not worn the watch regularly since then and had it stored away. I want to use it more regularly and have some beginner questions for the experts:

1. Winding: How many winds should I give a 1601 at first position? I’ve seen a range of 20 turns for partial wind (assuming I am wearing it some days) and 40 turns for a full wind (from no wear at all). Just want to make sure the 40 turns are okay for a 1601 and that it won’t “overwind” given its age.
   
2. Power Reserve: What’s the best way to test the power reserve? After doing a full wind (based on the answer to Q1), should I just set the watch down flat, note the date/time, and not touch it until it stops? Do I need to do the [power reserve test after the full wind from no movement or can I do the test setting it down with a partial wind after a few days of wear?
   
3. Time Test: What is the best way to conduct a time test with a 1601? Do I set the time using a specific site clock then come back after 24 hrs, 48hrs, etc. (noting any change in seconds/minutes)? Does it matter if I wear it during the time test or should it just lay flat and test time during the power reserve test?

I really appreciate you all chiming in on a fresh thread with these winding-related questions. I’m excited for my 1601 to make more appearances in 2024!

Sidebars:

• What’s the most reliable production date table based on serial number for vintage watches?
• What caliber is a 1960s 1601 likely running?

[watchnoob307]

1. can’t overwind automatic watches. they have a ratcheting mechanism to prevent the mainspring from exploding in case you walked around too much and the rotor kept spinning. hand-wind to your heart’s content
2. fully wind the watch and then set it down without touching it. since the watch was *relatively* recently serviced (it is coming up rapidly on needing a new service though), I doubt the mainspring has degraded significantly.
3. set the time against a known accurate watch (your smartphone) and monitor over the course of a few hours in the factory-adjusted positions. this is a pain in the ass if you don’t have a timegrapher. your watch may experience less-than-ideal performance since the oils may have settled or even dried by now with such little wear. ideally, you want to regularly wear your watch so the pivots can move and evenly coat the turning surfaces with oil, thereby reducing friction. after years of little-to-no-wear, your watch may run a bit poorly. far from damage, just may need another service. although 7 years really isn’t that long of a time. the aforementioned issues really are a concern for watches that sit unused for literal decades.

********

- can’t say much about serial number table accuracies
- caliber 1570

[Dan S]

What does "34" refer to in your post?

What are the first few digits of the serial number? There is a good serial number chart in the library forum of this site, and also on Vintage Rolex Forum.

As noted above, you can't overwind the automatic movement, feel free to wind as much as you want.

Strictly speaking, power reserve would be measured by doing a full wind (manually is most certain) and then leaving the watch unworn. It will stop when the friction in the movement is too much for the stored power to overcome. Testing the reserve after wearing it for a few days will give you somewhat different information, because it is also sensitive to the efficiency of the auto-winding mechanism, and potentially your level of activity.

As for testing time-keeping, both ways of doing it are fine, they just give you different information. One will tell you the timekeeping in one particular position, the other will give you realistic information about timekeeping on the wrist, which involves moving from on position to another. A watchmaker would carefully measure timekeeping in different positions separately.

[thejo]

Originally Posted by watchnoob307

3. set the time against a known accurate watch (your smartphone) and monitor over the course of a few hours in the factory-adjusted positions.

I appreciate the info! What are the factory-adjusted positions (as in different positions, dial up, down, etc.? I can start some testing today. To determine how slow or fast it may be running, is it just an average of several markers?


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[thejo]

Originally Posted by Dan S

What does "34" refer to in your post?

What are the first few digits of the serial number? There is a good serial number chart in the library forum of this site, and also on Vintage Rolex Forum.

The 34 is shown on the Rolex Service Centre card that came with the watch after servicing. It shows as model number: 1601/34

The serial is 1407XXX