Dial removal on Minerva stopwatch?

[MrRoundel]

Sorry for the double post. I inadvertently posted in the wrong forum. I hope the moderator(s) can delete it.

Greetings, folks. I know it's a shot in the dark but does anyone have experience to provide pointers on removing the dial on a Minerva stopwatch? There's an absolute dearth of information on the internet. That surprises me.

I have read that they are a bit tricky, but my friend wanted me to look at it to see if it can fixed economically. It's actually a fairly standard looking 3/4 plate watch. The plunger that is actuated by the crown is not operating. It's as if something either broke or slipped behind the dial. Unfortunately, the dial isn't an easy one. This is mostly due to the hands being very tight. I have read that this is the case, but I want to see if any one of our experienced watch experts have anything to say about getting behind the dial on a Minerva stopwatch. Anyone? Thanks ahead of time,. Cheers.

[MrRoundel]

After getting the go-ahead (with indemnification) to use a bit more force from the stopwatch's owner, I pried a bit more aggressively. The dial did come off with the hands still attached to their lower cam pieces. It turns out there is a broken coil spring under the dial. That's what we figured based on the action, or lack thereof, of the main button (Crown). I'll probably have to buy a parts watch to get one.

The next tricky part will be in re-setting the dial/hand unit. Surely the cams must be set just right relative to the return to zero position. Hopefully I'll figure that one out. Cheers.

Images included for the curious.

 

[MrRoundel]

I found an identical Minerva stopwatch on the bay. After replacing the broken spring under the dial it came time to figure out the setting of the hands. It was a bit tricky trying to get things to line up as I lowered the dial/cams over their respective posts. I ended up Scotch-taping the hands at the 12:00 position while I maneuvered the dial into place. Believe it or not, it worked. The dial screws were the cam style. It took some force to engage, but ended up grabbing.

While it seems there is little interest in stopwatches, I find them rather interesting. They're probably used as much or more in the general population than their time-telling counterpart, the pocket watch. And despite  having only 7 jewels, the Minerva movement is pretty well made. Not particularly valuable mind you, but neat. Cheers all.

 

Edited July 24, 2020 by MrRoundel

[MrRoundel]

I ended up buying a Meylan stopwatch that has a broken staff. It was under $10 shipped and taxed so I figured it was worth the lessons it held within. It has a broken staff. This probably happened whenever these things were banged around, as the solid balance is pretty beefy. I decided to remove the staff just to see what it was like.

It is a rather conventional friction-fit design so it was pretty easy to punch it out. I may even make a staff for it someday soon. Being that has a minimum number of critical dimensions, it should be relatively easy to make. The balance shoulder and hairspring shoulder are the same dimension. And the one-piece double-roller has the other critical dimension. The pivot is a rather massive .14mm.

If I can find a pre-made staff for it I probably won't fire up the lathe. We'll see on that one. As I said above, these things probably broke a lot of staffs so there should be some parts out there. I'll report back if I find either on the bay or dangling on the end of a piece of wire (As my old friend Charley used to tell me.).  Cheers all.