Horological Meandering

 " In order to guarantee optimum rate accuracy, the detent escapement has a highly uncommon and extremely hard to make safety system: an anti-tripping safety pin placed on the hairspring. A detent escapement watch starts to “trip” when the balance over-rotates, for example due to an impact, and releases the detent a second time, i.e. when a single balance oscillation releases two teeth on the escapement wheel, and therefore moves the small seconds hand forward by two seconds instead of one. To prevent this phenomenon, a pin is fashioned from a small steel bar and then threaded onto and fastened on the hairspring to prevent the detent from being released a second time. Since this pin measures 1.85 mm in length with a diameter of 0.07 mm, we can imagine the difficulty of making this part and positioning it with great accuracy on the balance to ensure that the safety system works ".