center wheel came apart

[dwhite]

I hope I'm not being a pain by asking so many questions.  I was taking apart an elgin pocket watch and when I removed the center wheel it fell into 4 pieces.  I have the shaft, the wheel, the pinion and what looks like a tiny washer.  I wasn't really looking that closely when it came apart so I can't be sure about the washer.  It looks like the shaft is keyed to the wheel and that the pinion threads onto the part of the shaft that sticks through the wheel.  But where does the washer go?  Also, how do you tighten the pinion without ruining the leaves?  Thanks in advance, Dan.

[wls1971]

What you are describing is a Elgin safety pinion you dont need to tighten the pinion very much because its supposed to unscrew its self if the mainspring snaps.

The wheel should have a d shaped hole to the center place it on the arbor so the d shape lines up with the flat on the arbor then put the washer on and then put the pinion on and screw it down it does not have to be tightly screwed down at all because when you reassemble the watch, when you wind it up the pinion will tighten its self with the torque from the mainspring.

Pictures paint a thousand words and you should endeavor to provide them in order to get an answer, not all Elgin center wheels are the same.

I am only assuming from your description it is a safety pinion pictures would help to confirm my assumption or may help someone else to answer your question.

[dwhite]

wls1971:  That makes complete sense, I hadn't thought of it.  I vaguely knew about a safety pinion but didn't know where it was located.  That means that the watch must have suffered a big power release, right?  The mainspring looks OK but I'll check again.  My wife showed me how to transfer a picture from my phone to the computer just tonight so I'll be able to in the future.  I'm a couple of decades behind on that stuff.  Thanks for the answer, I really learned something from it.  Dan.

[dwhite]

Oh, and the mainspring was off the hub.  Could that have done it?

[wls1971]

7 minutes ago, dwhite said:

Oh, and the mainspring was off the hub.  Could that have done it?

Yes that would certainly be enough to cause the safety pinion to do its job, you should inspect the barrel arbor for wear, and  replace the mainspring.