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Using a 2836 as a base for a small hand GMT project


chiman12

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I have received a few PM's on how I built my 1675 here.

Most often, members ask if using the Zodiac 75B is the best movement to use and what "trial & tribulations" did I go through to realize the final product. I still believe that a Zodiac 75B is the best way to go, as it accepts a gen-spec GMT wiith minor broaching, in addition ETA hour, minute and second hands can be used and the date wheekl spins the same way as a 1575. The downfall of the movement is that it is a vintage movement and is very difficult to find, which means that parts are hard to find.

There are other more practical movements to use, such as an ETA 2893-2 or asian GMT movements. These movements do work well, but since the modified 2836-2 GMT movements are so readily available, I decided to tear my 1675 apart and experiment and see if I can install a small GMT onto a 2836. Here is a shot of the 2836 that I will be using

P1014300.jpg

Now take into consideration, a gen-spec GMT hand post hole is too small to fit onto the GMT driving wheel of the 2836. The hand cannot be broach to increase the post hole diameter as this would remove the sides of the post and there would not be enough friction between the hand and the driving wheel to spin the hand.

So...creativity came into play. First off I located a spare ETA GMT hand in my parts box. I then proceed to broach the gen-spec hand until the post hole was the same size as the post hole on the ETA GMT hand, then I used fine sandpaper to remove and burrs.

P1014311.jpg

If you don't have broaches to widen the post hole, a needle file can be used. But file with caution and take your time, for the hand can easily snap off if too much torque is applied while enlarging the post hole.

The next step is to take the ETA GMT hand snip off the hand; as close to the post hole plate (for a lack of a better term!) as possible.

P1014313.jpg

Next, get some 600 or finer sand paper and lightly sand down the TOP of the ETA GMT post hole plate. Try to make it as thin a possible, but don't be over zealous. The reason to make it as thin as possible is to ensure that the overall height of the hand does not increase severely, because the installation of the hour/minute, and second will be difficult.

Next get your 200 watch screw driver and thread your gen-spec hand (bottom facing up) on the blade. Take some glue and apply it to the top of the freshly sanded ETA post hole plate and apply it to the gen-spec hand. The reason that the 200 screw driver is used, is that it is the same diameter as the post hole of the gen-spec hand. The screw driver acts as a guide to center the ETA plate with the gen-spec hand. The set up should now look something like this...

P1014318.jpg

A pic of a franken GMT hand!!

P1014314.jpg

Lets try installing it...

P1014310.jpg

Now install the rest of the hands, see if everything still works...always check the quick set date and GMT function, to make sure that the GMT driving wheel is still aligned...

P1014317.jpg

Proof that it is still the 2836 beating in the heart of my 1675 Cornino...

P1014319.jpg

Parting shots of the complete project...noticed that I refinished my GMT dial!!!

P1014328.jpg

P1014329.jpg

So, will the glue hold the ETA GMT plate and the gen-spec hand together? Yes...since no real force is applied to the joint, there is no reason why the two should delaminiate. My trial run of wearing it for a week will determine if my theory is correct or not!!! I guess you can always solder the two together when they are threaded on the screw driver, but the proper super glue should hold everything together.

SO....6542...COME ON DOWN!!!!!

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I went with freddy333's outline and pieced together the small arrow from a larger one. It was done pretty close to the way you did it, but I used 'low temperature solder paste'. I don't think that the temperature gets high enough through the crystal in direct sunlight to melt the glue, but I'd use an epoxy. I have read on another forum that the fumes from the 'Super bonder' glue is bad for the movement.

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Chi! Fantastic surgery, you definitely have a steadier hand than I plus the patience of Job to boot! :thumbsupsmileyanim: I can envision this as one of those exercises where I get half way through, make one slip, teach the cats some new vocabulary words, and hurl everything at the wall! :Jumpy:

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I can envision this as one of those exercises where I get half way through, make one slip, teach the cats some new vocabulary words, and hurl everything at the wall! :Jumpy:

I here you J...I here you...my dog knows quite a few of them!!!!

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Chiman,

do you use a standard eta movement ring, I have a 1655 that came with an Asian movement and I bought a 2893 GMT movement. I think is possible to install that movement on the case an the hands will clear the dial, do you have any advice for me?

Thanks

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I can envision this as one of those exercises where I get half way through, make one slip, teach the cats some new vocabulary words, and hurl everything at the wall! :Jumpy:

A few coincidences in this thread.

The solder paste works nicely but it takes a bit of practice, much like everything else in this hobby. My first attempt ended in flames and nothing recognizable. And when you apply the solder and it looks to be the right amount, you likely have too much and will have to sand that teeney - tiny little thing. The stuff will run using a match, so if you do it like a pro, using a torch as I did, just slowly ease the heat towards the piece. When the solder starts to run, take the heat away. I'd recommend practicing on some old hands to get the feel for the thin metal and the solder. GMT hands are not cheap, even the aftermarket ones from suppliers like Clark's. The cats leave the room when I put on my loupe. Much faster when I strike the torch.

And last night I reassembled my re-done 6542. It really looks great. But the ETA2893-2 stopped running. I triple checked everything, can't figure it out. But I must build a solid watch because when I heaved it at the floor it bounced a full foot off of it, and didn't have a scratch! Haven't seen the cats since. I used a Chinese movement ring and spacer ring, but I thinned them out to get the best fit I could. It fits nicely in the case. It still won't run, but it looks so good that I'm going to change it's nickname from 'Pussy Galore' to 'Fernando Lamas'.

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And last night I reassembled my re-done 6542. It really looks great. But the ETA2893-2 stopped running. I triple checked everything, can't figure it out.

Take the movement out of the case & see if it runs. If not, check to see if the hands are contacting each other. If it runs, check to see if the hands are coming into contact with the crystal. If neither of the above, r&r the stem to be sure it is seated properly. Sometimes, a simple r&r is all it takes.

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Take the movement out of the case & see if it runs. If not, check to see if the hands are contacting each other. If it runs, check to see if the hands are coming into contact with the crystal. If neither of the above, r&r the stem to be sure it is seated properly. Sometimes, a simple r&r is all it takes.

Thanks, Freddy. I have done that twice now, no joy. When I calm down a bit I will do a run through again. Just because watchmaking was rocket science before there was rocket science, I won't be intimidated!

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Joey...sorry to hear about the problems you are having...but with minor mods, the 2836 GMT actually runs really well, thus I can't see the reason to go to a $300 movement.

Chiman,

do you use a standard eta movement ring, I have a 1655 that came with an Asian movement and I bought a 2893 GMT movement. I think is possible to install that movement on the case an the hands will clear the dial, do you have any advice for me?

Thanks

Unfortunately I have never used a 2893 in my builds so I am no help here...sorry C! But Joey might have the answer for you.

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I've used ETA2836-2 in other builds with no issues.

Freddy, yes, out of the case, but with the dial still in place. Checked the hands and all the clearances. I'll likely dive in in all the way on Monday. I think it hates me...

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Joey...did you take off the hands and did the movement run again and are you using an aftermarket dial?

I found on many occasions that the post hole in the aftermarket dials are too small and the ETA GMT that is used would rub or catch on the sides of the aftermarket dial, causing the movement to stop. So I just broached the post hole on the dial a little wider, until the ETA GMT hand has enough clearance and not to rub against the edge of the post hole on the dial side.

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Joey...sorry to hear about the problems you are having...but with minor mods, the 2836 GMT actually runs really well, thus I can't see the reason to go to a $300 movement.

Unfortunately I have never used a 2893 in my builds so I am no help here...sorry C! But Joey might have the answer for you.

Which watch did you use to build this one?

Thanks

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@freddy, it's about a year old, so I'd be disappointed if it needs an overhaul already. It's more likely just something stupid I did. I had a similar issue when I first built it, turned out to be a dust fiber in the works.

@Chi, not yet. I'll get into it tomorrow. On this build I am using a Gen Singer dial that I highly modified. On the other builds I used the blank ETA dial from Otto Frei and yes, the hole needs to be enlarged for a GMT build.

If I find a cat hair in the movement I am loading up the .45...

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@freddy, it's about a year old, so I'd be disappointed if it needs an overhaul already. It's more likely just something stupid I did. I had a similar issue when I first built it, turned out to be a dust fiber in the works.

I hate to sound like a broken record about this, but, as has been said many many times, the movements in rep watches are either used, unserviced or both. If you plan to mod or keep a rep, its movement should be professionally serviced upon receipt. And, just to cover all the bases, (nearly) all mechanical movements should be serviced (disassembled, oiled & adjusted) every 5-7 years. Failure to do so is akin to running your car without having its oil changed.

Having a rep that ran for a year without problems, you should consider yourself lucky. But, now it is time to pay the piper.

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OK, it runs, sorta. The second hand hiccups or just stops at the 6 second mark. Smooth as silk around the rest of the dial, no interference from other hands. I even removed all the hands and ran the second hand only and it does the same thing. The slightest bump or touch gets it moving again. 6 is the devil's number, isn't it...

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OK, it runs, sorta. The second hand hiccups or just stops at the 6 second mark. Smooth as silk around the rest of the dial, no interference from other hands. I even removed all the hands and ran the second hand only and it does the same thing. The slightest bump or touch gets it moving again. 6 is the devil's number, isn't it...

Actually, it is 666.

Does the hand stop at 6 with the movement out of the case?

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