Just over a year ago I picked up a nice example of a Jumping Hour "digital" watch. So called because of the way the hours jumped from one to the next in the blink of an eye. Having only worn it a few times, I wanted to save any wear and tear until I could be confident that it had been serviced. The seller mentioned that he had been told it was recently serviced, but like all of us his take on it was "He said it was serviced, but you know how that goes." So a check on the Timegrapher showed me that it was now probably due for a service. First task was to remove the bracelet (which I had split in two earlier). It was then I found one of the stupidest bracelet to lug designs I have seen for a long time. The small spring bar sits in the central case lug and extends into each side of the bracelet end pieces. Access to the spring bar ends is via a blind hole and there are no holes in the outer sides of the end pieces. Arrrrrrgh! However, utilising my extraordinary "improvise, adapt, overcome" skills, and some "special tools" I was able to remove the pesky bracelet pieces without doing any damage. With that done, I was able to remove the caseback which revealed a nice clean movement, Caliber 2581. It was surrounded by a substantial movement ring to which the movement was clamped. I decided to use the ring as a movement holder while I started disassembly. So with the crown removed the movement was dropped out onto a pad and work was started on the dial side. Here you can see the hour and minute wheels and the copper coloured click spring that ensures that the hour wheel snaps into place once an hour when prodded by the big tooth you can see between the upper side of the hour/minute wheels. Hiding below a plain black plate was the date wheel. Looks really simple, can't be too hard! With the little wheels off we can see how the hour "jumps". The tooth or finger on the centre wheel pushes on one of the twelve knobs to move it anti-clockwise until the click spring drops into the next gap in the star wheel below it. The minute wheel just idles along, driven by a 1:1 ratio wheel below the disc. All I need to do us remove the plain black plate to finish off the dial side, can't be too much to that. Whoa Neddy! This is just as complex as any Omega day/date. Must remember to take lots of shots as I go along as I don't have an OEM parts diagram. More to follow.
I forgot to mention, I had previous coaching on this model. Can anybody remember who did something like this? Those involved need not apply.
Hi Jim I haven't seen one of your rebuild posts for a while but this one popped up in "latest". Looks an interesting project Cheers, Chris
Guilty as charged Jim. https://omegaforums.net/threads/something-a-little-different.27982/#post-313987
I wish I has @cicindela like skills with Photoshop so I could have @Archer, @Stewart H, @ChrisN and @François Pépin coming to my rescue.
Some observations post disassembly. I think there is MORE than enough grease here. Also note the swarf curl at bottom right. I'm not sure how long this bit of gunk has been getting a free ride, maybe it had something to do with the timing. There must have been a sale on braking grease! Use as much as you can, it's cheap today! Aside from a missing crown wheel screw these are the only issues with the watch. I think @Taddyangle was right to suspect the "recent service" advice he got. But there are some nice bits as well. Here's a shot of the balance pivot, the jewels have been removed for cleaning the balance in-situ. Look at that lovely regulator! And finally, a question for the gurus. When I was cleaning the jewels in the plates, I thought one was cracked (the lower "in-focus" one), but it looks like it's simply an imperfection in the jewel, a bit like a flaw in a diamond. Is this unusual or is it normal (if rare).
That jewel certainly doesn't look like it's cracked with that shape of flaw. Assuming you are 100% sure it's not a piece of lint (we all make mistakes..) then it must be in the jewel manufacturing process. I've not seen such flaws in Swiss jewels but you do see imperfections in Russian jewels, for example. At least I have. Interesting to see what the others say. Coming along Cheers, Chris
Hi Jim, Flaws in jewels are not completely unheard of, but they are not common. If I recall the last I saw were like bubbles inside the jewels - not that long ago and not sure I took a photo of it, but if I find it I'll post it. When I see a boatload of braking grease inside a barrel, I do start to worry that someone was doing that to get more amplitude, so it will be interesting what you get when you have this serviced. Looking at the sludge in that stem are in the first picture above, and some of the grooves, I would check the stem for burrs. Sometimes while filing the stem to length the file can slip and create a burr - this acts like a reamer in this area... Cheers, Al
Here is the original advertisement. I guess there are different definitions of what "serviced" really means... If I had a nickel for every time I have been told it was "just serviced". Its a very cool watch and I am glad you are enjoying it. I sold it back when I was thinking I was going to go only with Omega watches.
Found it....bubbles... Not the best photo but most of the little specks you see are small bubbles inside the jewel, and yes some dirt as well since this was taken before servicing. Small defects like this do show up from time to time, and most often they have no consequence for the functionality of the jewel. Cheers, Al
So where did we get to. The movement was cleaned and checked and everything went back together without any problems. One thing that took some figuring out was setting the motion works (the wheels on the dial side that make the hour and minute hands turn). On a normal calendar watch I pull the crown and turn until the date wheel just starts to move and then I set the hour hand to 12, do a couple of "days" to check it ticks over, and then I set the minute hand on its post again at 12. However there is no 12, just a numbered hour wheel that jumps. Looking at the dial plate, I noticed an index hole at about 10. So I did the usual of turning the crown until date wheel just started to move, then I set the "hour tooth" of the centre wheel in line with the index (shown below, but the tooth is at 12:30ish in this earlier shot). My understanding was that the tooth has just flicked the numbered hour wheel from 11 to 12, so setting the hour wheel with 12 opposite the centre wheel and letting the centre wheel run until the date clicked would synchronise the hour wheel. Next was to set the minute wheel. I did this by advancing the centre wheel until the hour wheel just started to move, and then set the minute wheel with "00" opposite the centre wheel. Checking by turning the crown showed that the hour wheel was jumping at about 55 minutes, so I loosened the minute wheel and set it forward a bit. Testing again showed that the date clicked over every send pass that the hour wheel jumped to 12, which happened just as the minute wheel came up to "00". With the movement in the case and the dial side done it was time to do some final tweaks to regulate the movement and then re-fit the auto wind mechanism. So here was the base movement ready for adjusting/regulating and waiting for the autowind mechanism which still has to be cleaned, inspected, assembled, lubricated and fitted (please excuse the grease smudge on the ratchet wheel, I applied a spot of grease to the wrong side before fitting ).
Next step is the Auto Wind Mechanism (AWM). This interesting in the way that Tissot (and Omega) achieved bi-directional winding with a relatively simple and effective approach. The rotor post has two cogs engaging it via a notched plate (see red arrow). As the rotor turns clockwise (CW) (as per the picture below), the cogs rotate in an anti-clockwise (ACW) direction. When mounted, the notched plate loosely engages a pin (red arrow) on the AWM bridge and as the rotor turns one way, friction moves the plate so that one cog can engage and turn the first winding wheel (silver wheel just visible below right of the rotor post). As the rotor changes direction, friction moves the plate in the other direction until stopped by the pin so that the first winding wheel is always turned in the same direction. The first winding wheel also has a click spring so that it can only ever turn clockwise, thus transmitting torque to the second winding wheel ACW and the third winding wheel CW. The lower pinion of the third winding wheel engages and turns the crown wheel ACW (see post above) which rotates the ratchet wheel CW, thus winding the mainspring. I think it may be called a wig wag system but I'll have to investigate further.
Now that you've all digested that, I'll move on to stripping and cleaning the AWM. No surprises here just a plate with two screws that retains the first and second wheels and a click spring with one TINY screw. The third wheel is held to the bridge by a finger that engages a groove in the shaft of the wheel. The wig wag cogs and plate on the rotor aren't removeable. After stripping we have this, all ready to be cleaned. As my cleaning methods are constantly evolving, I thought run through the way I cleaned this lot. First up is a scrub of the dried grease and oils using a soft toothbrush for plates, and a stiff paint brush and pegwood for jewels. The basic tools. Following that is an ultrasonic cleaner to loosen any debris and clean out parts the brushes and sticks can't reach. Then a proper clean in the watch cleaning machine, shown here going through the first jar containing cleaning fluid. (Thanks to a tip from Al, I now demagnetise the basket of parts before going into the cleaning machine). After a spin dry, into first and second rinses and then into the drying chamber while being spun slowly. And the result of all that work? Here's an example.
Time to close off on this one. After reassembly was completed it was onto the winder for a few days to settle down. Timekeeping was really good and a day or two wearing it showed good performance. A Timegrapher shot taken today at DU shows a very big difference to the first one here: Today: Amplitude is still about the same, maybe it's normal. @Stewart H ? And here is is on the wrist. Ignore tha date setting, as long as the actual function works I don't care as I can't see it without my specs on .
Nice job Jim and an interesting watch. The amplitude is not that high but, if you've just built this, it will pick up a little over the first week or so. I'm not familiar with this calibre but, will look up the lift angle unless you've already confirmed it? I usually build the base movement with just the minimum to make it run and then test that. With that method, you can see if adding all the gubbins (bit of a technical term there) is causing a drop in amplitude. Things like friction springs can kill amplitude if badly adjusted as can any bad parts. It also means that you are not stripping large parts of the movement if you decide to investigate. What is the amplitude like in other positions and after 24 hours? Oh and your post brought to mind "My eyes are dim, I cannot see, I have not brought my specs with me". Old Scouts song... Cheers, Chris
