Help Junghans B 12 #140 clock movement


NAWCC Member
Apr 3, 2022
Eureka, CA
Looks good. If it runs, you must have got the size right. The Loctite won't hurt anything. :)
In the next to the last pic, it looks like one trundle might be broken. Maybe just the pic.
Thanks for the reply yes the first pic was of when I discovered it broken. Two of the trundles snapped from the spring breaking. I'm happy no teeth got knocked out as well. Changed the broken spring. The only one the correct size was a few inches shorter than the original, hopefully won't make a huge difference? I think it was 4 or five inches shorter.

About to put it back together for the second time now that the lantern pinion seems good to go. Last time I got the plates together I stupidly moved the anchor depth and learned quite a great deal about how hard it can be to find the right depth again, hard for me anyway! A little nervous about setting up the correct orientation of the strike/chime locking pins. I'm looking in the Conover book chapter on the B 10 (the one I'm fussing with is a B11) on page 84 but he doesn't indicate any particular orientation at all.

I see the article that new2clocks posted (very helpful!) says, "The Count Wheel (chime locking plate) can be moved on its arbor, to synchronize it with the maintenance cam. You don't need to split the plates to synchronize them.". Is there a particular tool to use? Seems very firmly in place. I tried to rotate it by hand and it seems immobile. I am trying to put it together like the close up photo shows, but if I did have to move it with a tool I don't want to hurt it!
Last edited:


Registered User
Mar 3, 2019
Rod, there are two types of pinions used in clock making, lantern pinions and cut pinions. Pins (trundles) are used in lantern pinions. Here’s one:
Thanks. That is a new term to me - trundles. In fact, one clock I worked on had a broken one which I was able to replace from an old wheel/lantern. At 81, there is always something new to learn! Rod.
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