American PW Waltham 1908 question

[Al J]

I have a 17 jewel Waltham pocket watch here, and it's giving me some difficulties in the winding. It does wind for a bit, and then the crown wheel and winding pinion start to slip once the tension on the mainspring starts to build up.

Photos of the movement before disassembly:



The winding pinion has a bit of wear on the teeth, but not much. It does seem to have some play on the stem, but I'm not sure if this is contributing to the slipping or not:



The teeth on the crown wheel do not come to a point, but it looks so even that I'm not sure if this is wear or what it should look like:



Here you can see the profile of the teeth:



I know the mainspring isn't slipping in the barrel, because I can wind the watch using a screwdriver in the ratchet wheel screw. I also know it's not the winding and sliding pinions slipping, because I've marked across them both and they stay together when the slipping starts, so it's in the crown wheel and winding pinion.

So, do I need a new winding pinion and crown wheel? If so, can anyone provide me with the correct part numbers, as I don't have any Waltham reference material.

Thanks very much.

Cheers, Al

 

[psfred]

I've had a similar problem with two watches -- an Elgin 450 and a Elgin 345.

In the case of the Elgin 450, I did not have the ratchet wheel installed correctly, and it would slip on the crown wheel when some tension was wound in. I corrected that by getting the ratchet wheel properly seated on the mainspring arbor. This is a very thin watch, and the shoulder on the arbor is thinner than usual.

On the 345, the problem is that the sleeve is not adjusted correctly in the case, and the stem is in between winding and setting. On some watches with negative set stems (stem in the case, socket in the plate), there is an adjustment cam provided to match the watch and sleeve to get proper action. If this cam isn't set correctly, the clutch on the stem will slip rather than the crown wheel and winding pinion.

Peter

 

[doug sinclair]

The crown wheel core on these (the "hub" of the crown wheel) has a blind hole on the underside which fits over the head of the screw which holds the shim (under the crown wheel) in place. I'm certain you have the core seated properly over that screw head? (pardon me for asking, if you have it in place).

 

[Al J]

Winding and sliding pinions are not slipping, as I mentioned before. The ratchet wheel is also set properly.

Thanks, Al
-> posts merged by system <-

The crown wheel core on these (the "hub" of the crown wheel) has a blind hole on the underside which fits over the head of the screw which holds the shim (under the crown wheel) in place. I'm certain you have the core seated properly over that screw head? (pardon me for asking, if you have it in place).

This one has a through hole in it, and it is set over the screw properly.

Thanks, Al

 

[psfred]

Blacken the teeth on the crown wheel where they are driven by the pinion using a Sharpie, install, wind until it slips, and then remove the crown wheel. The ink will be rubbed off where the teeth contact, including where they slip if they do.

It appears that the crown wheel is not engaging fulling with the pinion. That could be due to several things, including a worn stem, worn socket in the plate for the stem, wrong pinion, improperly fitting crown wheel (unlikely as it would not engage the ratchet wheel properly), and so forth.

Never safe to assume that the watch was correctly fixed the last time it was worked on, which could have been decades ago!

Peter

 

[AbslomRob]

Does it slip if you use a winding pin while the movement is out of the watch? Is it possible that the stem on this case simply isn't long enough?

 

[Al J]

Follow-up

I had another 1908 come in recently, and today I looked at the teeth on the underside of the crown wheel from the more recent 1908 - they were not as worn as those in my photos above were. I tried the crown wheel from the later watch, and it wound fine, so now on the hunt for a new crown wheel for the original watch.

Thanks to those who offered solutions.

Cheers, Al

 

[ben_hutcherson]

PM me-I have a cigar box full of 1908 parts and probably have one