Help Junghans 103 rating

Mike Brown

Registered User
Dec 13, 2019
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I'm overhauling a Junhgens 103 movement. The rating assembly consists of a disk with a spiral groove, and a tapered pin fixed through the top of the suspension spring assembly, with the free end riding in the spiral groove. Rotating the disk raises and lowers the suspension spring. In my case, the pin is badly bent.

Questions - is this the original pin? If so, why would it bend as it has? If it's not original, should I replace it with a tapered pin or a straight pin, and should I use steel or brass?

IMG_0050.JPG Junghans 103 pin.jpg
 

Uhralt

NAWCC Member
Sep 4, 2008
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I think it should be possible to straighten the existing pin. I guess it got bent when somebody continued turning the spiral with some force even though the end of the range of adjustment had been reached. If you need to replace the pin, it should be steel. It seems the original pin was tapered. Maybe that is necessary so that one end fits tightly into the hole in the spring assembly and the other one into the spiral without too much friction.

Uhralt
 

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Rockford's early high grade movements by Greg Frauenhoff