Asian 7750 to Swiss 7750 movement swap question

[jun]

Have a watch with a swiss 7750 and another with an asian 7750. I would like to swap them. My problem is that the swiss movement have chrono minutes at 12 and the asian has chrono minutes at 3. I think the date wheel is not going to be a problem but Im not sure about the hands.

Can this be done? Can the minutes gear be swaped from 12 to 3 within the movement itself ? Can the hands be swapped between movements?

Thanks

[anton]

That depends on which version of the A7750 you have:

Low-beat versions hand sizes are the same as the Swiss 7750.

High-beat versions have different size posts than the Swiss 7750.

The minutes transfer from 12 to 3 are just the addition of three gears that transfer the function from position A to B. You can use those parts and bring them over to the Swiss 7750.

[jun]

That depends on which version of the A7750 you have:

Low-beat versions hand sizes are the same as the Swiss 7750.

High-beat versions have different size posts than the Swiss 7750.

The minutes transfer from 12 to 3 are just the addition of three gears that transfer the function from position A to B. You can use those parts and bring them over to the Swiss 7750.

Its a high beat version, I assume the hands will be the "stop" to the upgrade. Correct?

[musicale]

I believe the holes in the hands for the Asian can be gently enlarged to fit the Swiss movement, obviously reversing this is more tricky.

[anton]

Upgrading is still possible. Your avenues:

Do It Yourself if you can break down and put back together a 7750

Contact a watchsmith who will take on the job

Contact The Zigmeister (but he may be booked solid for the next two-three months)

or get 7750-equivalent hands.

[Toadtorrent]

If I remember right...you only need to change 2 of the hands...the centre seconds and I can't remember the other...running seconds I believe but I don't have time to search right now. I'm not sure if the different formats of the 7750 make a difference on this though.

[PAMman]

On the older, 21,000 bpm Asian movement all the hand sizes are the same as the Swiss ETA 7750. However, the 28,800 Asian movement has a smaller center seconds hand and larger hands on all 3 subdials when compared to the ETA.

[anton]

I believe the holes in the hands for the Asian can be gently enlarged to fit the Swiss movement, obviously reversing this is more tricky.

The subdial hands are 0.17mm and the centre seconds are 0.25mm on the ETA 7750. On the A7750, they are 0.20mm. So your old hands won't fit (the centre seconds can be broached to fit, though.)

The hour and minute hands are interchangeable, however.

[jun]

Thanks for your support

[techd]

With the right equipment you should be able to enlarge the holes veerrrry carefully. You'll need a reamer tool with the precisely sized heads that'll let get you to 0.17mm and 0.25mm.

Might try this myself someday...someday far far away lol.