Waltham Crescent Street: How to disassemble the mainspring barrel???

[LittleWatchShop]

1 hour ago, JohnR725 said:

The definition a railroad timekeeping is interesting.

I watched a video about Ball Watch Company with interviews from NAWCC members.  Very interesting video.  That is where I got the 30 seconds.

Were there ever any RR hack watches?  Seems like if you are trying to maintain such accuracy, you want to know where the second hand is supposed to be, no?

Another thing.  The point of accuracy was to avoid train wrecks.  Why not build into the system model, certain error tolerances and relax the requirement on the watch.  Cost of moving less freight?  Fascinating stuff, really.  We take all this for granted since we have an atomic clock in our pocket.

____________

My journey...going on about 2.5 years is progressing from coarse to fine.  At the beginning, I was happy not to lose parts and get a watch running reasonably well...then actually making various parts for the watch (screws, springs), to fine-tuning my oiling skills, and such.

This watch has inspired me to try to get the most I can out of a watch...at least more than I have tried in the past.

Too many years behind me to ever be great at this, but I will continue to set my goals beyond me and enjoy the journey.

[cwuz]

On 1/4/2023 at 8:10 AM, LittleWatchShop said:

Good news...and bad news.

As best I can tell, the thread pitch on that screw is 148.

CORRECTION:  I believe it is 120.

This is a message from the future but I'm recording for posterity.  I had the exact same issue with disassembly on a Crescent St (model 1908) and ended up breaking the ratchet wheel screw in exactly the same way (though in my case the screw head shattered into four pieces). However, once the screw broke, the arbor actually came apart really easily; it wasn't actually seized at all and there was no other damage.

So I thought about it a bit and when the Waltham guide says to "use the ratchet wheel as a key" you DO NOT WANT TO SCREW THE RATCHET WHEEL DOWN FIRST.  If you look at the diagram and think about it, when you are trying to unscrew the arbor into two pieces, the ratchet wheel screw is in the way of the arbor coming apart, and the ratchet wheel is putting a lot of upward pressure on the screw head.  That's why the head popped off in the way it did, because there was no room for expansion with it screwed down (except for it exploding).

So in summary, I think if you just hold the loose ratchet wheel and use it like a circular wrench, the whole assembly should come apart pretty easily.  I hope this saves someone in the future from this same mistake.  As for me, a cheap 7j donor movement and a mainspring are on their way!

[LittleWatchShop]

19 hours ago, cwuz said:

This is a message from the future but I'm recording for posterity.  I had the exact same issue with disassembly on a Crescent St (model 1908) and ended up breaking the ratchet wheel screw in exactly the same way (though in my case the screw head shattered into four pieces). However, once the screw broke, the arbor actually came apart really easily; it wasn't actually seized at all and there was no other damage.

So I thought about it a bit and when the Waltham guide says to "use the ratchet wheel as a key" you DO NOT WANT TO SCREW THE RATCHET WHEEL DOWN FIRST.  If you look at the diagram and think about it, when you are trying to unscrew the arbor into two pieces, the ratchet wheel screw is in the way of the arbor coming apart, and the ratchet wheel is putting a lot of upward pressure on the screw head.  That's why the head popped off in the way it did, because there was no room for expansion with it screwed down (except for it exploding).

So in summary, I think if you just hold the loose ratchet wheel and use it like a circular wrench, the whole assembly should come apart pretty easily.  I hope this saves someone in the future from this same mistake.  As for me, a cheap 7j donor movement and a mainspring are on their way!

Let us know how the donor screw works.  Which 7j movement did you buy?

[cwuz]

I got a 7j 610 grade movement for about 20 bucks, which is the same Waltham Model 1908 as the Crescent St. but in hunter configuration.  The ratchet wheel screw was in fact the same diameter/thread pitch, but the barrel dimensions were slightly different so the screw was a little long.  I filed it down and now it's working perfectly, you can't tell it's a replacement at all.  I needed a few other random screws from the donor movement (dial screw, one of the balance jewel screws), and those were all identical and worked perfectly.

With the new mainspring the Crescent St is humming along nicely, though running too fast, so I still need a few balance adjustments before wrapping up this project