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A mini pocket watch from Elgin
Very small movement. The trend through the 1940's & 50's was to make a point of how small the 'modern' wristwatches were by comparison to the old fashioned pocket watches, but this piece itself is then cased as a (tiny) pocket watch...
The watch does not run in its current state. Let's see if we can breathe some life back in to it.
Judging by the well worn case & generous helping of pocket grime around the seams, this watch looks like it served as someone's everyday timepiece for many years, not just as a mini-sized novelty & keepsake.
The balance wheel turns freely. Good sign, no broken balance staff pivots which can be a common point of failure.
But, the going train (sequence of timekeeping gears) does not advance.
Will have to get deeper in to the movement to find the cause of the failure.
Watchmaker's dial paper between the hands & dial to protect the dial surface.
Dial screws in the side of the mainplate to secure the dial.
Dial washer & hour wheel.
The dial washer pushes lightly against the underside of the dial, keeping the hour wheel in place.
Hand remover tool.
Doesn't actually do a great job of removing the hands, but I find it very useful in pulling off the friction fit cannon pinion.
When squeezed, the white Teflon blocks on the outside push down & the pincers on the inside clamp together & pull up.
That's as much disassembly as we want for now on the dial side.
Over to the watchmaker side of the movement
Want to get the balance out early on, both to give it a close inspection but also to get this very fragile & critical component out of the way of accidental damage.
Balance looks good from the top side.
Flipping it over to check the underside we can see the problem...
Empty hole where the impulse jewel should be.
The impulse jewel (assuming it hasn't fallen out & disappeared...) moves with the balance wheel & engages with the pallet fork.
For each oscillation of the balance wheel, the impulse jewel both unlocks the pallet & then in turn receives an impulse from the pallet to propel the balance forward on its next oscillation.
Here, the balance is free to swing back & forth all it wants, but with no impulse jewel the balance can never interact with the rest of the watch movement, & the rest of the watch movement can only remain frozen in place for all time.
The Elgin 647 is not a rare or expensive movement, so for less than $20 on eBay a donor balance can be sourced.
Can see the ruby red impulse jewel present & accounted for on the new replacement part.
The forked end of the pallet is reaching out to receive the impulse jewel, but in
its current state the balance will just swing by with no effect.
The third wheel pinion extends up through the bridge & turns the large brass intermediate center seconds wheel. This then turns the smaller center seconds pinion that extends through to the dial side & turns the second hand.
The way the added hardware for the center seconds stands alone & above the plane of the rest of the movement makes it quite obvious that this function was grafted on to & on top of an existing movement design. No pretense of the center seconds functionality being natively integrated into the rest of the movement.
The second wheel (concentric to the seconds pinion) partly covers some of the downstream going train. Removing this next will clear the way for those other downstream parts.
Barrel bridge & a clear view of the second wheel & the
mainspring barrel.
The original mainspring is fatigued, & does not uncoil back into its ideal contours.
Luckily New-Old-Stock parts remain available for many of these old Elgin watches, once again for a reasonable price off of eBay.
Old mainspring above, new below.
Last of the watchmaker side parts.
Train bridge.
Fourth wheel & escape wheel.
Back to the dial side for the remaining breakdown
The setting lever spring & minute wheel cap are integrated as a single part.
Clutch, winding pinion, setting lever, setting lever screw, & winding stem.
Uncommon to see a pocket watch with the Incabloc shock protection, but the 1940's & 50's were a transition phase between pocket watches & wristwatches.
The Incabloc jewel system allows for the balance staff to shift & rock by a small amount & protects against impacts that could otherwise snap off the very delicate end pivots.
Hole jewel & cap jewel.
Broken down & ready for the cleaner.
In to the ultrasonic bath.
Two cycles of cleaning followed by three cycles of rinse & this watch is ready to go back together
Lower balance jewel assembly.
Once cleaned, the tiny measure of lubricant gets held in place by surface tension.
Back into the chaton, & held in place by the Incabloc spring.
And the same for the upper balance jewel.
Reassembly of the keyless works (winding & setting).
And of the motion works (gearing together of the hour & minute hands)
Dial side (mostly) complete, now over to the watchmaker side
Fourth wheel & escape wheel.
Train bridge.
New mainspring into the barrel.
Little bit too much grease on the inside of the barrel cap.
Second wheel & mainspring barrel.
Barrel bridge.
Click, ratchet wheel, & crown wheel.
Center seconds pinion.
Time has come to get the escapement put back together,
see if this little heart wants to beat again...
Can see the very small measure of lubricant on the end facet of the pallet jewel.
And the moment of truth...
There it goes.
Wonder how many years (decades?) since this old watch last ticked.
Let's check on the timing
That's pretty bad. Minutes per day fast, & a large beat error of 5.6ms. The beat error indicates that one direction of oscillation for the balance wheel is larger than the other.
It's hard to see, but if you look closely you can see how the pallet is pulled over to the left when the balance is at rest.
Need to very slightly rotate the hair spring collet around on the balance staff. This has the effect of adjusting the position of the hairspring stud on top relative to the impulse jewel underneath. Doing this results in the impulse jewel moving over to being on center, & then bringing the pallet along with it.
I have put down some witness marks on the outer edge of the balance wheel in order to help me judge how much the hairspring stud is moving.
Before.
And after.
Can see the very small amount that the collet has been rotated by, just 1 - 2 degrees.
The beat error is much improved, from 5.6ms down to 0.8ms with just that small adjustment to the position of the hairspring collet. But, still gaining minutes per day...
The balance screws are installed at the factory to bring the balance into poise. This serves to reduce or eliminate any heavy spot on the balance wheel, same principle as balancing a car tire.
This balance wheel does seem to have good poise, & this is good for timekeeping consistency throughout a variety of positions, but the watch is still running fast. To address this we can add a pair of timing washer under two of the balance screws on opposite sides of the balance wheel.
This is not so easy...
The balance screws & timing washers are probably the smallest parts in the watch, & handling & manipulating these without launching them across the room is a challenge.
How small are we talking?
Well, here's two of the timing washers...
Maybe add in one of the balance screws for scale?
How about a grain of salt?
Grain of rice?
There we go...
As with all things in watchmaking, there's a special little tool just for grasping the very small balance screws.
Hard to see, but have managed to capture a timing washer on the balance screw.
And that's looking good now for timing.
Always impressed to see the timekeeping accuracy that some of these old movements can achieve.
Fitting the cannon pinion.
The cannon pinion is what the minute hand will get fixed to.
Can also see the seconds pinion emerging out through the hollow tube of the second wheel.
Hour wheel & dial washer.
Fitting the dial.
I'll case the movement now & install the hands last, try & minimise the handling of the watch with the hands unprotected.
In the home stretch for the reassembly...
When applying the hands it's important to ensure that each hand is square & level. If any of the hands end up even a little bit off kilter then the slightest touch between hands would be enough to stop the watch.
Looks like good clearance for the minute hand.
Hand stack looks good, but will let the watch run for a day to make sure nothing gets hung up.
Last piece.
Yes it's a pocket watch, but still dwarfed by a modern wristwatch.
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