Setting the incorrect hand stack GMT ETA style 2836 movement

[FxrAndy]

Setting the incorrect hand stack GMT ETA style 2836 movement

This movement was designed as a day date movement by ETA and has been modified with a GMT function by adding an extra GMT hand under the hour hand. Driven from the day/date drive.

The main function of a GMT is the ability to view Greenwich mean time (or any other time zone you wish) on your wrist and also your local time, this function is most useful today for travellers who wish to know what time it is at home in comparison to where they are, I found this function useful for avoiding phoning home at 4 in the morning rather then 4 in the afternoon when overseas.

Originally the need to know GMT came from the needs of sailors and navigators in order to ascertain Longitude, for more on this subject a visit to the Maritime Museum in Greenwich London would be useful and I also recommend the film Longitude with stars such as Jeremy Irons and Michael Gambon to name but two. A full explanation can be found on wikipedia and a small exert is here, for UTC read GMT.

“Longitude at a point may be determined by calculating the time difference between that at its location and Coordinated Universal Time (UTC). Since there are 24 hours in a day and 360 degrees in a circle, the sun moves across the sky at a rate of 15 degrees per hour (360°/24 hours = 15° per hour). So if the time zone a person is in is three hours ahead of UTC then that person is near 45° longitude (3 hours × 15° per hour = 45°). The word near was used because the point might not be at the center of the time zone; also the time zones are defined politically, so their centers and boundaries often do not lie on meridians at multiples of 15°. In order to perform this calculation, however, a person needs to have a chronometer (watch) set to UTC and needs to determine local time by solar observation or astronomical observation.

So now we know what it is useful for how do we set the watch. For this explanation I will be referring to turning the crown clockwise and anti clockwise, by looking directly at the face of the crown you will see which is which.

This movement has a 3 position crown

that means that from is fully depressed or rest position (unscrewed on a screw down case) it will be in position 1 this is the winding position (it is not recommended to hand wind the 2824/36 ETA style movements due to the fragility of the winding mechanism, better to rock the watch in your hand so that the rotor its self will wind the main spring a little to get the movement going then wear the watch) If we were to wind the watch in this position it we would have to turn the crown clock wise.

I wish to set the date, time and GMT indicator to 2nd of the month 1500hrs or 3:00pm central European time and the GMT showing GMT (1400)

For the next two setting I always first pull the crown to the third position and set the time to 6 am to ensure that the date change mechanism is fully disengaged this will become apparent later why*

Position 2 is with the crown pulled out to the first click. This is the date and GMT set position. In order to set the date we turn the crown clockwise and the date wheel will quick change to the date you want, I always go to the date before the one I want

Main Hands should now be showing 0600 date 01 GMT at whatever

I will now pull the crown to position 3 and wind the main hands forward through 12midnight where the date will change to 02 and I can set the time to 1500hrs or 3:00pm CET. This is the reason we set the date to the date before to ensure that we know that the time is set to AM or PM and to ensure that the date will change close to midnight and not midday

Main hands now showing 1500hrs or 3:00pm CET date 02 GMT whatever

If we now push in the crown back to position 2 (it may be easier to push back to position one and them back out to 2) we can now turn the crown anti clockwise moving the GMT hand the the required position of 1400hrs (7 o'clock on the main dial)

Main hands now showing 1500hrs or 3:00pm CET date 02 GMT 1400hrs GMT

The crown can now be depressed to position 1 and screwed down if required,

The watch will now show local time (for me in central Europe)

And GMT being read from the GMT hand using the outer bezel.

I hope you find this interesting and understandable

PS the film longitude is available to down load as a torrent via isohunt.com

[Chronofan123]

Thanks, thats really useful info.

[By-Tor]

Excellent writeup FXR.

Where exactly you want this to be moved... I'll do it?

[FxrAndy]

Just made a quick edit, i had the date and GMT movements back to front it is clockwise for the date and anti clockwise for the GMT

@ BT i think it should be in tech help and info

[By-Tor]

I actually made a similar tutorial a few years ago. Great minds think alike.

[FxrAndy]

And i even had a look about for one before (just not hard enough)i wrote this for Chronofan123 who bought my EX2 asked for instructions, so i thought i would write them for all to see

@Chronofan123, have a good read of BTs one as well, he generally writes clearer than me and his pictures are about a million miles better than mine

[By-Tor]

Actually I forgot that I even wrote the whole tutorial... but when I read your post I started thinking... "hmm... didn't I make something like this once". Went to my section and there it was. I guess it's early Alzheimer's already.

PS: Thread moved... dunno if members can post replies in this section though.

[FxrAndy]

As long as Chronofan123 can read it along with other it will be fine

[aajaxx007]

Longtime member who just got his first 2836 GMT.  Had given up setting the GMT hand until I came across this post, now I'm all set (pun intended).

 

Cheers!