Manual Planting Of Gear Broken Shaft Tenon

This is an old 18K gold Piaget watch. This kind of old watch was not waterproof in the past. Its movement model is 12PC1. The shaft tenons of its two gears have rusted off one end. If you want to find such accessories, it may only be available from the original factory, but the price will not be cheap, and the fastest time may be half a year. If we planted it by hand, wouldn’t it be cheap and fast? Left: cleaning a new watch part; right: assembled watch movement
     01: Due to the water ingress, the shaft and tenon of these two gears are rusted and one end is broken, and these two are only the gears of the automatic part, and the gears of the moving part are not rusted at all. So as long as the watch is wound by hand, it is completely walkable.
    02: Use a caliper to measure the shaft tenon of this gear is 0.5mm, and the broken tenon is at the toothed end. The diameter of the plane that can be drilled at this end is larger than the shaft diameter, so even if a bit larger than 0.5mm is used, it is only After making the tenon, grind it to 0.5mm. Because the drill bit tends to be thinner and harder to grind, and the thinner the bit is easier to break. In fact, I used a 0.4mm drill bit, so the drilled hole diameter is about 0.5mm, and the tenon that is planted is exactly 0.5mm. Basically no further processing is required. 03: In order to maintain the original rigidity of the part being processed, I choose a harder drill to directly drill the cross section, the so-called ‘cold drill’, instead of annealing the broken shaft and then drilling, the ‘hot drill’. However, the key to drilling is not here. The most important thing is that the drilled hole must be in the center of the cross section, that is, on the axis. Otherwise, no matter how good it is, it will be a waste of effort, and it will be impossible to remedy or even scrap … So in Do not rush to drill before drilling, but to locate first, you can first smooth the cross section, then use a finer drill to point the hole, select the center position, and then slowly drill. When drilling 0.2 ~ 0.3mm, it is determined that there is no Deviation, you can drill down quickly. 04: The drilling depth is about the same as the length of the tenon, and then a round rod with a diameter of about 0.5mm is used for trial insertion. If it feels slightly tight, it is estimated that it can be inserted in place (completely based on feeling). At this time, remove the round rod. Add a little bit of ‘green oil’ into the hole and then gently tap the round rod into place with a hammer. Bake the prepared tenon at high temperature for 10 minutes and take it out. The tenon won’t fall off if you clamp it with tweezers. Or add a little solder to the planting place to weld firmly. This completes the planting of the mortise. In fact, after the tenon in the picture is planted, I have worn it again, and it is slightly thinner than the lower tenon. 05: The pinion of this pinion is easily and well prepared using the aforementioned method. And there is no tooth on this axle, it can be used to make a whole axle. After the two shaft tenons are completed, the entire automatic part of the gear is loaded into the movement, and the automatic hammer is turned. If the two-way rotation is very flexible, it is done. This is a ‘Pearl Tuo’ automatic watch. Clean and refuel the movement, complete the assembly, and adjust the speed. Originally a watch with severe rust, after nearly a month of immersion, derusting, and then ‘joint’, it finally resurrected …