Staking Tool (I). Making a Spare Ratchet Wheel for A7750

[Francisco]

One common failure of the Asian 7750 is that some tooth of the ratchet wheel are broken. In such a case the watch has very poor power reserve. Unfortunately, the ETA spare is not compatible, because pivot diameter is too large.

A picture of a broken ratchet wheels follows, showing the broken teeth:

The measures of the pivots for Asian and ETA ratchets follow:

Asian 7750: 0.19 mm

ETA 7750: 0.27 mm

One approach to solve this problem is using a lathe, as shown here:

Without a lathe, another approach is assembling the central part of the Asian ratchet in the gear of the ETA part. It is like making a

[caruwe]

Very big cinema

Thanks