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Date Wheel Swapping for Hublots or similars

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Another excellent one from Francisco.


How to swap the date wheel (DW) on A7750 has been discussed a lot on rep forums and there are some tutos available. However, the swap is quite more difficult when the A7750 has the minutes at position 3 (a modified A7750). This tuto shows the issues to take into account in this case.


The example shown here is a HBB with DW with original black text and white background. The owner wants to install a DW with white text and black background.




The final result will be this:








As always, hands and dial must be removed:






Following picture shows the mechanism when the dial is removed. As seen, the modification to move the minutes from 12 to 3 is above the DW, and it has to be removed to swap the DW. The mod consists of 3 gears.




To remove the mod, the 2 screws marked have to be removed. After removing the plate fastened by these 2 screws we will see this:




Next step is to remove the 2 gears located more to the right, with no difficulty. However, when assembling, later, central gear, it is easy to confuse top and down faces. That is the reason I marked top face with a black marker (red circle).


The two gears removed:




Now we have one of the new problems in comparison with the standard DW swap: removing the gear at 12. This gear is pressed on the minutes output pin…and it has to be removed very gently…otherwise we may brake the output pin for minutes. Very important, we have to remove the gear, without producing any horizontal stress on the pin.


There are several options to remove this gear safely:


1.- Using a pair of small screwdrivers, making a lever. Or using a similar tool for extracting hands . Be careful, we are not removing hands…this is a more delicate task. Remember not to make any horizontal force.


2.- A specific remover for this task, very similar to the tool for removing hands, see next picture:




The tool I have is for gears with 5 “armsâ€. However, the gear of the mod has 4.

It can be used, but it is a bit risky as it can produce horizontal stress on the pin.


3.- Finally I employed a tool form Bergeon, for removing hands and gears, shown in following picture:










As two last pictures show, the top and down faces of the arms are different. One is flat, and the other one is curved. This design permits to remove the gear safely, without breaking the pin.


Follows the procedure to use this tool. The tool is placed under the gear, both arms are hugging the output pin. Flat face up.




Then we rotate the tool as the arrows show. The toll rotates itself over the curved surface of the arms, lifting up smoothly the gear a bit.


Then we repeat these steps after pushing more the tool to the gear. Finally, the gear is free.






Next picture shows the output pin for minutes. Red circle shows that the tip has been modified to fit better with the hole of the gear.




Next step is to remove the two screws shown in next picture:




Then remove the plate shown, very carefully, or a spring will jump. Anyway, have ready a magnet-bar always you dissemble a movement.




Next step is to remove the spring and lever shown by the red arrows:




Next step is to remove the screw and small plate shown by next picture. These pieces are not found on a normal A7750.




And now it is possible to swap the DWs. Black ETA DW installed:








Now it is time to reverse all the previous steps. First task is to assemble the small plate:




Time to assemble the spring and lever. This is not easy… spring tends to jump. Best approach for me is fastening the spring with a small wood rod. However, some people prefer to use Rodico.






Top plate is assembled. Time to check that date change works.




Assembling gear at 12 is easy:




Central gear is easy because top face is marked:




Previous picture shows a hole for the third gear. This hole is extremely small, as the gear pivot is really small. Therefore, it is very easy to break the pivot… assemble with lot of care.




Final step is the plate that fastens the gears:




And the final result:




Thanks for reading,



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Another great tutorial - thanks for the re-post Onze :D

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That ain't exactly like changing the oil in your car.

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That ain't exactly like changing the oil in your car.



Can one do that himself.

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