More and more Hamilton model 21 marine chronometers popping up on the MB. Lets service one. This is not showing the whole process by any means, but it gives an idea. This is one I did for a client about 15 years ago. He bought it broken, I fixed it, he made a killing when he flipped it. I didn't charge him enough!

Picture marked 17 shows a brass wire, a ruby rod, and a steel pin. The jewel is the detent jewel in a detent escapement. The original jewel likely had been broken during a previous botch job, and it had been replaced with a steel pin! Here we are replacing the steel pin with a proper ruby jewel.
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