Unusual Mainspring Barrel Configuration

Anybody come across one of these?

Some time ago I got an alarm pocket watch from a friend of a friend who needed to get it fixed as it wasn't working properly.
I explained that a 75 year old pin lever, stamped plate movement wasn't exactly designed to last as long as a quality Swiss movement.
However, I did my best and got it running/functioning.

Some months later, I got a call, "the hands are not turning, can you fix it"...........
This is despite telling the owner that while it worked when I finished it, the watch should not be used as a reliable timekeeper but put on the display shelf as a vintage curio.

Anyway, it's back. The problem is the method of drive from the mainspring barrel to the hands.

Unlike a standard gear train, the mainspring barrel only drives the gear train from the barrel to the escape wheel and the time keeping/setting is driven by a friction wheel fitted to the top of the main barrel.

Over time, the "friction" that was between the two components has deteriorated due to wear, primarily because the time setting from the crown wheel to the minute pinion must turn the "friction wheel".

I think I can restore the friction by using a dome punch on an anvil and hopefully strike a balance between 50/50 friction, enough to drive the hands against the drag of the alarm wheels and enough to allow setting the time without twisting the stem into a liquorice stick.

Photos follow to explain things.

Any hints or tips as to resolve this issue?

Well, THAT is cursed... What in the thunder sort of demon juice were they drinking when they designed that?

So am I to get this right: You wind the spring, and it unwinds from BOTH sides of the spring (outside for alarm, center for motionworks?)? So when you wind it, the friction-wheel there slips as well? That would be clever if it weren't so insane.

As another throw-away idea: you could perhaps add silver-solder to the center of the friction surface then ream it to a size that provides a good amount of friction.

Else as said above, press out the bushing and replace it/remake one, or peening the brass bushing might help. IF it were a little bigger, I'd suggest center-punching INSIDE (basically a poor-man's knurl). You MIGHT be able to take a close fitting reamer and do a 'less than 1 tooth' cut to rise a burr but not break it. But that could just as easily make it worse rather than better.

The friction wheel, or as I now call it, the Devil's Wheel, is an integral part of the barrel cap.



From the underside of the barrel cap you can see where the spacer disc that sits between the barrel cap and the Devil's wheel is peened onto the cap. There is a fixed centre tube pressed into the cap/disc for the barrel arbor.



The top view shows the inseperable parts.



The only way I can see to restore some friction is to expand the top end of the arbor tube. Removing and replacing anything would be a fool's errand I feel.

Here is a short video showing how loose the Devil's Wheel is.

Thats actually easier, it looks like you just have to tighten the rivet? Perhaps just use a staking set to tighten the rivet?

Being unable to seperate the components without permanent damage I decided to leave it intact.
Maybe I could get a super fine grease gun and inject some braking grease? <joke>
After much thought, I figured out the only solution was to go with a minor expansion of top of the arbor tube.
A tapered dome stake and some gentle taps, with some friction checking between hammering seems to have improved things.




Off to put all back together.

I think you're right Al.

Anyway, all back together and running. So much going on under the dial!



The rear side isn't to be outdone in complexity either. The click and the ratchet wheel sitting on top of the alarm driving wheel. When the alarm goes off, every wheel you see there is spinning 🤪.



I'll give it a couple of days to see how it performs before returning it.

Note, temporary minute hand fitted just so I could see it still running.

No, the stake was only expanding the top couple of millimetres and there is a significant amount of the tube unaffected as it's constrained by the spacer disc and the lid.