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Center wheel replacement questions

WatchmakerWannaBe

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May 25, 2013
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I recently re-built a Waltham model 1873, and I believe that it needs a new center wheel. After cleaning and reassembling the watch, I noticed that the center wheel was bent (or had a bent arm). I managed to straighten the wheel, and believed that I had solved the issue (passed backlash test). I also however noticed what looked like a section of the wheel's teeth that looked like they were still dirty even after the wheel went through the ultrasonic. Upon closer inspection, it's clear there's a section of gear teeth that are scored - presumably from someone running the watch with a bent wheel and the pinion leaves must have done a number on the wheel teeth. Here is a shot of the teeth on the center wheel:

Pic2.jpg

I decided to look through an assortment of old Waltham train wheels and parts that I bought long ago, and I believe that I may have actually found a matching wheel (I have to count the teeth though, but it looks like a match).

Assuming it is a match, I'm thinking my staking set is the tool to use to remove the center wheel pinion on the old wheel and install it on the new wheel. If this is so, then which stakes should be used? Assuming of course, that pinion is friction fit to the wheel. Here is a shot of the other wheel I found:

Pic1.jpg

This kind of problem is probably for a someone with more experience than me...
 

gmorse

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Hi Steve,

The scoring on the face of the wheel shouldn't cause any problems unless there are tiny burrs raised on the acting surfaces of the teeth. If there are, then the best way to remove them is with a topping tool (or an Ingold's Fraise if you can find one); that's another tool for your collection, and could be a wallet-drainer! If not, then I suggest that although it may not look good cosmetically, removing the wheel and replacing with another which may not run at the same depths is a step too far. Setting a new wheel so that it runs true really needs a lathe to do it properly.

Regards,

Graham
 

WatchmakerWannaBe

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Thanks Graham.

This watch runs very well for a few hours perhaps, but then it will stop - I was planning to take note of the position of the center wheel each time it stops by marking one of the teeth with a fine tip sharpie (black ink). When I rotate the watch (sitting in the movement holder), it will again run for a while before stopping again... This watch was passing the back lash test beautifully too. I even inadvertently performed the backlash test when blowing dust from the movement - A jet of air hit the escape wheel which first rotated it forwards...and then it rotated backwards.

The watch does however have a bit too much end shake (staff is a bit short). I have some extra replacement staffs for this watch, but they have thicker pivots (they are identical in every other way - designed for later 1873 models ). So I plan to use my Jacot tool to attempt pivot reduction...from 0.14 mm to 0.11 mm. Actually, I succeeded already in doing this on a practice balance, and it was working very well...Until I was in the process of removing the balance from the tool, when the bow tipped over. This (via horse hair thread) spun the drive pully which in turn moved the drive arm right into the path of the exiting balance - snapped a pivot! I was removing the balance in order to clean the bed runner in preparation for burnishing. lol. I've now learned that it is wise to lock the drive pully whenever I'm either installing or removing the balance from the Jacot tool (with drive arm out of the way as well).

Anyway, I will remedy the staff situation first and then go from there...I may need a lathe sooner than I thought.

Is it possible to determine if a replacement wheel will run at the same depth (assuming teeth mesh depth) by inspection or by measurement? Assuming that the original wheel is of course burred on the acting surfaces of the teeth... The center wheel may not even be the problem. I'm hoping to find out soon.
 
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gmorse

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Hi Steve,

Actually, I succeeded already in doing this on a practice balance, and it was working very well...Until I was in the process of removing the balance from the tool, when the bow tipped over. This (via horse hair thread) spun the drive pully which in turn moved the drive arm right into the path of the exiting balance - snapped a pivot! I was removing the balance in order to clean the bed runner in preparation for burnishing. lol. I've now learned that it is wise to lock the drive pully whenever I'm either installing or removing the balance from the Jacot tool (with drive arm out of the way as well).
Yes, been there, got the tee-shirt . . . I usually just hook the bow behind the vice bar to stop it being unruly.

Is it possible to determine if a replacement wheel will run at the same depth (assuming teeth mesh depth) by inspection or by measurement? Assuming that the original wheel is of course burred on the acting surfaces of the teeth... The center wheel may not even be the problem. I'm hoping to find out soon.
What you need for this is a depthing tool . . .

Regards,

Graham
 

WatchmakerWannaBe

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Thanks again Graham.

I've marked 3 of the teeth with a tiny dot of ink (stuff comes off easily). I going to try and determine if the wheel is stopping in the same place (or places) each time the watch stops. I took note of the first stoppage, and then will take note again (probably several times) to see... I'm skeptical now though that it's the center wheel or any of the train wheels/pivots given the back lash test results (multiple tests), and by observing how freely the train wheels move when restarting the watch (rotating movement sitting in movement holder).

You are talking about the same depth tool type for measuring the distances between train wheel pinions - or where the holes for the train wheels go in the plate(s)? I think these tools can be had for a reasonable sum...if one shops a bit...
 

gmorse

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Hi Steve,

Depthing Tool.jpg

Yes, one of these. If you set it to the centre distance of the two holes concerned, you can check the depthing between the third wheel pinion and the centre wheel.

Regards,

Graham
 

WatchmakerWannaBe

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Update and new question concerning my model 73.

I don't believe the center wheel is the problem - I'm happy to say. But, now I think the problem is in the pallet fork assembly.

The watch will run now without stopping in the dial up and down positions (greased the pallet stones with Moebius 9415), but it will occasionally stop when transitioning from the dial positions to one edge position. It appears as though one of the pallet stones is not unlocking. I believe this to be the case because upon removing the balance and testing the snap of the fork between the banking pins, it snaps well in one direction, but not so much in the other direction. This seems to coincide with the edge position that stops the watch - where the snap back of the fork has to defy the gravity of it's own weight.

I haven't yet re-checked slop on the fork - end shake/side shake, and I have to also examine the pallet arbor and pivots. Perhaps one of the pallet stones is not mounted correctly (although they do not appear to be loose)? This problem has been with this watch from the start... I would just like to know if anyone else out there has had this sort of problem, and if so, what did the source of the problem end up being?
 

GeneJockey

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Update and new question concerning my model 73.

I don't believe the center wheel is the problem - I'm happy to say. But, now I think the problem is in the pallet fork assembly.

The watch will run now without stopping in the dial up and down positions (greased the pallet stones with Moebius 9415), but it will occasionally stop when transitioning from the dial positions to one edge position. It appears as though one of the pallet stones is not unlocking. I believe this to be the case because upon removing the balance and testing the snap of the fork between the banking pins, it snaps well in one direction, but not so much in the other direction. This seems to coincide with the edge position that stops the watch - where the snap back of the fork has to defy the gravity of it's own weight.

I haven't yet re-checked slop on the fork - end shake/side shake, and I have to also examine the pallet arbor and pivots. Perhaps one of the pallet stones is not mounted correctly (although they do not appear to be loose)? This problem has been with this watch from the start... I would just like to know if anyone else out there has had this sort of problem, and if so, what did the source of the problem end up being?
I had one on which the receiving stone was mounted backwards. When I checked the snap, it was good in one direction and sluggish in the other. I took the pallet out and looked, and it looked right. But that's because the inexperienced eye EXPECTS the receiving pallet to have the opposite of the angle of the discharging stone, rather than a slightly different angle.
 

WatchmakerWannaBe

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Thanks Gene.

I think I read something similar that newbies do when it comes to pallets stones in Fried. I think the angles are correct on both stones - I compared them to another pallet from another model 73.

I will have to take a closer look at the whole thing. Actually, I also noticed that when I rotate the watch from a dial position to any edge position, the balance also slows a bit, before resuming it's normal rate. Could this suggest too much side shake or end shake in the pallet? The balance is just right I think...
 

GeneJockey

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Thanks Gene.

I think I read something similar that newbies do when it comes to pallets stones in Fried. I think the angles are correct on both stones - I compared them to another pallet from another model 73.

I will have to take a closer look at the whole thing. Actually, I also noticed that when I rotate the watch from a dial position to any edge position, the balance also slows a bit, before resuming it's normal rate. Could this suggest too much side shake or end shake in the pallet? The balance is just right I think...
Dunno. I had a problem putting an Elgin 452 back together this weekend. It's one of those where both hole and cap jewels come out and are held in place by the cap jewel screws. The hole jewels are identical top and bottom, but because one cap jewel setting was shiny and the other was dull, after cleaning I assumed the shiny one was the top. I spent at least an hour trying to solve the problem of WAY too much endshake, such that the watch would run with excellent amplitude DD, but would sometimes STOP DU. Or it would run with great amplitude.

FINALLY I looked at the OTHER chatons on the bridges and noted they were dull, too. Swapped the cap jewels and the endshake problems disappeared and the thing runs great at all angles.
 

WatchmakerWannaBe

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Thanks again Gene.

I had to replace the cock hole jewel, using one from a donor movement....although the donor jewel setting looks like it may be a plate hole jewel...The pivot side of the jewel setting is more concave than the original setting in the balance cock - perhaps somebody else used the wrong jewel in donor movement...But then again, the end shake and side shake look right. And I don't think that that issue (if it's an issue) would effect the snap back issue on one banking pin...

Balance jewel replacement is more often than not, one of the most troublesome issues of re-building a watch, but it teaches me a lot.
 
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