Why the CHS GMT movements are failing

[KJ2020]

Dude you have probably forgotten more watch lingo than ive ever learnt but i think i get where your coming from. If the gluing keeps failing i think my idea i showed in the pic should work as its a permanent mechanical lock that in theory cant fail. I dont need independently adjustable gmt as im sure most people dont. Which wheels are you looking to remove? Are you thinking make it so the quickset just makes both the hour and gmt spin around quicker together? Its a pain in the ass trying to set a date using just the normal time setting method (crown all the way out). If its 0.15mm i could probably just get some shim and have a crack but i know making things that tiny will be a nightmare.

OK since I don't have a spring to try to re-make or repair, I'm going to see about a permanent glue fix. Regarding the quickset date fix, once the hands are locked, there is no longer a need for either of the two intermediate wheels linking the date corrector to the GMT wheel. After their removal, the date corrector is free to resume its normal function. You can see in the top pic below that the date corrector gear does not sit in a slotted hole in this movement like it does on a normal 2824, so the movement plate would have to be filed to create the slot. This could be easily done, there's a forum member would completely skeletonized a Daytona by hand.

I'm hopeful I can do this, I just wish I had more parts. If anyone has a dead CHS movement they want to contribute to this effort, please PM me.

BTW both the 2836 and DG2813 / DG3804 ICHS movements will fit and function in a 2824 CHS case.

https://forum.replica-watch.info/fo...swap-your-chs-movement-to-ichs-is-it-possible

 

[Dr Fun Socks]

OK since I don't have a spring to try to re-make or repair, I'm going to see about a permanent glue fix. Regarding the quickset date fix, once the hands are locked, there is no longer a need for either of the two intermediate wheels linking the date corrector to the GMT wheel. After their removal, the date corrector is free to resume its normal function. You can see in the top pic below that the date corrector gear does not sit in a slotted hole in this movement like it does on a normal 2824, so the movement plate would have to be filed to create the slot. This could be easily done, there's a forum member would completely skeletonized a Daytona by hand.

I'm hopeful I can do this, I just wish I had more parts. If anyone has a dead CHS movement they want to contribute to this effort, please PM me.

BTW both the 2836 and DG2813 / DG3804 ICHS movements will fit and function in a 2824 CHS case.

https://forum.replica-watch.info/fo...swap-your-chs-movement-to-ichs-is-it-possible

I see what you mean man. Is it a blind hole or a through hole on the plate? If its through cant you just use a small needle file to elongate the hole? How exact does it have to be? If all goes well ill be getting a lathe this weekend so ill start on making the wheel fixing adaptor next week but it will be a pain in the ass making the 2 small triangular teeth. Might end up filing the lower gear to have 2 flats and go that direction.

 

[KJ2020]

I see what you mean man. Is it a blind hole or a through hole on the plate? If its through cant you just use a small needle file to elongate the hole? How exact does it have to be? If all goes well ill be getting a lathe this weekend so ill start on making the wheel fixing adaptor next week but it will be a pain in the ass making the 2 small triangular teeth. Might end up filing the lower gear to have 2 flats and go that direction.

The hole goes all the way through. The silver-grey you see there underneath the hole is the mainspring barrel. It only needs to be maybe 3-4mm. Piece of cake with a small file.

 

[Dr Fun Socks]

The hole goes all the way through. The silver-grey you see there underneath the hole is the mainspring barrel. It only needs to be maybe 3-4mm. Piece of cake with a small file.

Is the width important? Only thing is the main plate has that extra spindle for the date change so messing up could be a disaster. Date mechanism is nothing like on a normal 2824. You can get a set of 0.9mm - 1.5mm diamond files on the bay for about £15, ive just ordered some to help making the spring replacement.

 

[KJ2020]

Is the width important? Only thing is the main plate has that extra spindle for the date change so messing up could be a disaster. Date mechanism is nothing like on a normal 2824. You can get a set of 0.9mm - 1.5mm diamond files on the bay for about £15, ive just ordered some to help making the spring replacement.

It has to be wide enough to allow the date corrector post to slide. It's maybe 1.5 mm. Can you post a pic of the underside of your date corrector I didn't have one with my movement and want to see if it's an identical part. Thanks.

 

[KJ2020]

Pics of the two intermediate date wheels

 

[Dr Fun Socks]

It has to be wide enough to allow the date corrector post to slide. It's maybe 1.5 mm. Can you post a pic of the underside of your date corrector I didn't have one with my movement and want to see if it's an identical part. Thanks.

No worries man ill open it back up later. Can you point out where the date corrector is haha. I can make the watch work but i have no idea what the parts are all called, ill get there my bad!

 

[KJ2020]

No worries man ill open it back up later. Can you point out where the date corrector is haha. I can make the watch work but i have no idea what the parts are all called, ill get there my bad!

Sure bro, I labelled it in a previous pic. I'll post up a regular 2824 later showing the slot beneath it that this one needs to modified to look like.

 

[Dr Fun Socks]

Sorry man i should of just scrolled up!

So it seems the glue is rock solid. I cant get the two halves to turn separately at all. Only reason i can think the watch is loosing time would be the little wheel that connects the gmt wheel to the date and hour wheels. Maybe i didnt press the dial down hard enough as that seems to stop that wheel wiggling about.

 

[KJ2020]

Sorry man i should of just scrolled up!

So it seems the glue is rock solid. I cant get the two halves to turn separately at all. Only reason i can think the watch is loosing time would be the little wheel that connects the gmt wheel to the date and hour wheels. Maybe i didnt press the dial down hard enough as that seems to stop that wheel wiggling about.

Agreed, if the upper and lower halves of the GMT wheel are locked then the link between it and the hour wheel is the only possible point of failure. 4 gears are in play at this point, so obviously the teeth on all 4 gears must be checked and ruled out. If all teeth are intact, then there has to be a disengagement. The GMT and hour wheels should be solid on the canon pinion, leaving only the modified intermediate date wheel as a potential culprit. Mine feels very solid on its pinion, it only rocks when lifted up some. Your mention of the dial contact made me wonder about using a small washer epoxied onto the back of the dial directly above the IDW (intermediate date wheel) to keep it from popping up. I've seen this concept used in reps before (not glued but spot welded). I trust JB Weld epoxy. Need to investigate further.

 

[Dr Fun Socks]

Agreed, if the upper and lower halves of the GMT wheel are locked then the link between it and the hour wheel is the only possible point of failure. 4 gears are in play at this point, so obviously the teeth on all 4 gears must be checked and ruled out. If all teeth are intact, then there has to be a disengagement. The GMT and hour wheels should be solid on the canon pinion, leaving only the modified intermediate date wheel as a potential culprit. Mine feels very solid on its pinion, it only rocks when lifted up some. Your mention of the dial contact made me wonder about using a small washer epoxied onto the back of the dial directly above the IDW (intermediate date wheel) to keep it from popping up. I've seen this concept used in reps before (not glued but spot welded). I trust JB Weld epoxy. Need to investigate further.

Yeah i was 99% sure it was the intermediate date wheel. Still might be. But i rebuilt the watch again today and just after 3 the hour hand stopped moving for about 2 hours. The gmt wheel, which is just the gold thing that slots over the hour wheel has kept perfect time all along and that runs from the intermediate date wheel. The minute hand has been spot on. I think there must be an issue at some point on the hour wheel teeth, when in setting mode its spot on but when its running is when the issues arise. I think there must be some damage to some teeth somewhere. Im guessing it will be impossible to get a replacement too

 

[KJ2020]

The gold wheel on top in this pic is the hour wheel. You can see its mounting pinion for the hour hand sits below that of the silver GMT wheel which is in two halves. It should be easy to tell if any of the gold hour wheel teeth are bad, if not since the GMT hand is keeping proper time, it is either the top gear teeth on the IDW or a disengagement issue there.

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[KJ2020]

Here's a side view for interested readers. The GMT wheel in this pic is not glued together so its top half is a little askew, but the gears are connected correctly.

In a normal ETA movement, the minute wheel drives the hour wheel. In the CHS movement, the minute wheel drives the GMT wheel at (1), the GMT wheel drives the IDW at (2), the IDW drives the hour wheel at (3), and the datewheel driving wheel at (4). There are teeth on the IDW at (5) that are not connected to anything. The two intermediate wheels at (6) can and should be removed as they are nothing but drag on the GMT wheel in this scenario of a reduced functionality CHS movement.

 

[kennygconspiracy]

Here's a side view for interested readers. The GMT wheel in this pic is not glued together so its top half is a little askew, but the gears are connected correctly.

In a normal ETA movement, the minute wheel drives the hour wheel. In the CHS movement, the minute wheel drives the GMT wheel at (1), the GMT wheel drives the IDW at (2), the IDW drives the hour wheel at (3), and the datewheel driving wheel at (4). There are teeth on the IDW at (5) that are not connected to anything. The two intermediate wheels at (6) can and should be removed as they are nothing but drag on the GMT wheel in this scenario of a reduced functionality CHS movement.

Fascinating! This is exactly the content that is probably some of the finest and pushes the boundaries of knowledge accessible to common non-watch repairmen!

Sent from my ONEPLUS A6003 using Tapatalk

 

[KJ2020]

Here's some pics of the 2836 date corrector gear. The center hole on top looks smaller than your CHS gear, but that should be of no consequence. It's only the bottom post and bottom half (larger teeth) gear that would be used to restore the quickset date feature. Interestingly, your lower gear has 20 teeth, my two have 19 and 18. So apparently that doesn't matter. The datewheel has 31 teeth of course, this lower gear is what engages the datewheel teeth.

In this pic, you can see how the mainplate would have to be modded to allow the quickset date feature to be restored. Easy peasy, just look at this post.

https://forum.replica-watch.info/forum/rolex-tudor-replicas/7995820-squeleton-4130-daytona

 

[Dr Fun Socks]

Here's some pics of the 2836 date corrector gear. The center hole on top looks smaller than your CHS gear, but that should be of no consequence. It's only the bottom post and bottom half (larger teeth) gear that would be used to restore the quickset date feature. Interestingly, your lower gear has 20 teeth, my two have 19 and 18. So apparently that doesn't matter. The datewheel has 31 teeth of course, this lower gear is what engages the datewheel teeth.

In this pic, you can see how the mainplate would have to be modded to allow the quickset date feature to be restored. Easy peasy, just look at this post.

https://forum.replica-watch.info/forum/rolex-tudor-replicas/7995820-squeleton-4130-daytona

Yeah i 100% get what your saying. I think its a great idea. Ive got an old eta 2824 in parts i could take all the date change wheels from. As you say, slot will be easy to make. I think the difference of one tooth is irrelevant if your going to change that wheel out anyway. It would probably work even with that wheel it would just change 1/20th of a turn slower than with a 19t. If i can get my bloody hour hand to work ill definitely look into it! Cheers for all the help you really are some kind of wizard!

 

[Dr Fun Socks]

I dont suppose anyone has any idea which movement the intermediate date wheel is from? Closest thing ive been able to find is this from an esa 9180. The fact they’ve crudely ground off the teeth of the second to bottom wheel makes me think it’s definitely from something and not a custom part like the gmt wheel. This looks very close.

 

[KJ2020]

I dont suppose anyone has any idea which movement the intermediate date wheel is from? Closest thing ive been able to find is this from an esa 9180. The fact they’ve crudely ground off the teeth of the second to bottom wheel makes me think it’s definitely from something and not a custom part like the gmt wheel. This looks very close.

Great thinking! Replacement part would be a real bonus.

 

[Dr Fun Socks]

Great thinking! Replacement part would be a real bonus.

Its a bloody needle in a haystack man! Theres a very similar part in a rolex 3185, with the exception of its not hollow, it slots into a jewel at either end. That and ifs about £150...
Tickleshoes have you come across anything similar in any other movements? Im a bit of a noob when it comes to taking movements apart. I know its not in a 2824 or a miyota 9015 haha!
The ‘similar’ rolex part:

 

[KJ2020]

Well we see where they got the idea from. Could always break that spindle off the 2824 movement and drill a little hole in the plate, haha.