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AP Diver with low-beat 2824, success


sneed12

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I had a couple of days off of work and decided to play with my AP diver a bit.
 
As most of you know, the gen AP diver has a 21,600bph movement. Our reps come with an ETA 2824 (or clone) movement which beats at 28,800bph. If it had a 2836 movement, it would be simple to swap in a 2846, which is the exact same movement except with a 21.6 beat rate. However, swapping a 2846 for a 2824 is more difficult. It's typically doable (although the stem height is sometimes an issue), but the date wheel will not swap and with these AP divers have a custom date font, so using the stock ETA wheel is no good.
 
Vac posted a thread in his section that seems to indicate that he's modified some 2846s to work with the 2824 datewheel, so I tried that for a bit. I swapped every single part on the front of the 2824 to a 2846, and it still would not work correctly with the 2824 datewheel. The teeth are not in the right plane. Some people report success so there apparently is a way to do it, but I couldn't figure it out and no one will share with me how it's done.
 
So I decided to do it from the other side of the movement. In a lot of ways this is actually more desirable, since it gives you a movement with the correct stem height, you don't have to modify the date mechanism, etc. It is more delicate, fussier work though, and some of the parts are very easy to break.
 
What I ended up with was a movement with all of the 2824 parts except the balance wheel, pallet fork, and escape wheel. The gear train is the same on all of the 28xx movements so nothing else had to be swapped. Now the movement beats at 21,600bph and nothing on the front side of the movement had to be changed. I didn't even remove the stem or uncase the movement.
 
These are the parts that were swapped:
6A75E14C-44AB-4EBB-8C57-392423EF4B9A-461
 
I've transplanted these parts to the clone A2824 (you can see that the balance **** arm doesn't have the same perlage finish as the rest of the movement--this pic is through the loupe, that's why it's so weird looking)
933FF260-5FF2-4D6E-A001-F6382DC1EF09-461
 
Better pic:
E02D3B61-18E0-4F60-B5B3-DCB122CDE9BC-461
 
Watch is now running at 21,600 bph. I didn't even have to touch the dial and hands or uncase the movement! The watch itself actually makes a pretty good movement holder for this project.
F6B76DDA-A95B-4ECD-9EE0-265C2ECFE655-461
 
Excited by how this turned out. Watch has been running within about 3 sec/day for the last day and a half, we'll see what it settles in at--the lower beat movements usually aren't quite this accurate over the longer term. Waiting on a new strap, I bought a Donerix leather, we'll see how it looks all together.
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Wow, great info ! This falls into "why-didnt-I-think-of-this" category  :) Well, I guess it never occurred to me that 2846 and 2824 have identical gear trains ...

Anyhow, I think this is by far the best way to modify diver movement to low-beat config.

 

regards

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Great to hear sneed! I posted a question not long ago curious if this was possible Would you be kind of enough to answer some questions via pm once I find the time to work on my similar setup?

 

Would rather answer questions here in the thread... these forums are for sharing information, and someone else might have the same questions as you someday.

 

Having said that, I posted pretty much everything you need to know. You need to remove the escape wheel (which means removing the plate that holds the gear train), balance assembly, and pallet fork. Then install the same parts but from the 2846. There is literally nothing else to it.

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  • 2 weeks later...
  • 4 weeks later...
  • 6 months later...

 

I had a couple of days off of work and decided to play with my AP diver a bit.
 
As most of you know, the gen AP diver has a 21,600bph movement. Our reps come with an ETA 2824 (or clone) movement which beats at 28,800bph. If it had a 2836 movement, it would be simple to swap in a 2846, which is the exact same movement except with a 21.6 beat rate. However, swapping a 2846 for a 2824 is more difficult. It's typically doable (although the stem height is sometimes an issue), but the date wheel will not swap and with these AP divers have a custom date font, so using the stock ETA wheel is no good.
 
Vac posted a thread in his section that seems to indicate that he's modified some 2846s to work with the 2824 datewheel, so I tried that for a bit. I swapped every single part on the front of the 2824 to a 2846, and it still would not work correctly with the 2824 datewheel. The teeth are not in the right plane. Some people report success so there apparently is a way to do it, but I couldn't figure it out and no one will share with me how it's done.
 
So I decided to do it from the other side of the movement. In a lot of ways this is actually more desirable, since it gives you a movement with the correct stem height, you don't have to modify the date mechanism, etc. It is more delicate, fussier work though, and some of the parts are very easy to break.
 
What I ended up with was a movement with all of the 2824 parts except the balance wheel, pallet fork, and escape wheel. The gear train is the same on all of the 28xx movements so nothing else had to be swapped. Now the movement beats at 21,600bph and nothing on the front side of the movement had to be changed. I didn't even remove the stem or uncase the movement.
 
These are the parts that were swapped:
6A75E14C-44AB-4EBB-8C57-392423EF4B9A-461
 
I've transplanted these parts to the clone A2824 (you can see that the balance **** arm doesn't have the same perlage finish as the rest of the movement--this pic is through the loupe, that's why it's so weird looking)
933FF260-5FF2-4D6E-A001-F6382DC1EF09-461
 
Better pic:
E02D3B61-18E0-4F60-B5B3-DCB122CDE9BC-461
 
Watch is now running at 21,600 bph. I didn't even have to touch the dial and hands or uncase the movement! The watch itself actually makes a pretty good movement holder for this project.
F6B76DDA-A95B-4ECD-9EE0-265C2ECFE655-461
 
Excited by how this turned out. Watch has been running within about 3 sec/day for the last day and a half, we'll see what it settles in at--the lower beat movements usually aren't quite this accurate over the longer term. Waiting on a new strap, I bought a Donerix leather, we'll see how it looks all together.

 

 

I know, old thread, but I was curious: How did the accuracy turn out after it settled?

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  • 4 months later...
Dear sir,
 
I've read your topic on the rebuild of a 2824 to a lowbeat and looking in to do the same:
How did the accuracy tur out after it settled.
 
I need to bring mine to a watchmaker since I'm not a watch maker ;( is it possible you provide me the parts or part numbers I need to order. In the picture I see more parts then you state. I see a balance wheel (+ bridge?) a Pallet fork a Pallet bridge and a escape wheel. Do I need to order all or is the balance wheel bridge and pallet bridge the same as a 2824?
 
Thank you for your time and hopefully you can provide me the information :)
 
Kind regards,
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Escape wheel: http://www.ebay.com/itm/Escape-wheel-spring-705-eta-2801-2-2804-2-2824-2-2834-2-2836-2-2846-/400292449599?pt=LH_DefaultDomain_0&hash=item5d334a0d3f

 

Pallet fork: http://www.ebay.com/itm/Escape-wheel-spring-705-eta-2801-2-2804-2-2824-2-2834-2-2836-2-2846-/400292449599?

pt=LH_DefaultDomain_0&hash=item5d334a0d3f

 

Balance wheel : http://www.ebay.com/itm/Genuine-Balance-Wheel-Complete-Bridge-Calibre-ETA-2824-2-/231129644901?pt=LH_DefaultDomain_0&hash=item35d0667f65

 

 

I think it would be better off purchasing an ETA 2824-2 / ETA 2846 and taking out the parts out of the movement to make this mod more cost effective.

 

Also i am considering getting the standard ETA 2824-2 date wheel. I've heard from other members that it will not fit due to the gear issues. 

Is that true?

 

My only concern is whether the date cyclops is wide enough to display the date itself.

Edited by JTZL
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  • 1 year later...
  • 8 months later...

I know, old thread, but I was curious: How did the accuracy turn out after it settled?

Took a while to settle, but in the end got it regulated to within a few seconds / day

Wonder if the 2840 can be a donor for these parts as well. 

Possibly -- not sure if they would fit

Note that the 2840 has a nylon pallet fork and escape wheel...

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