I got this Hamilton 992B Railway Special late last year and was rather pleaded with it.



However, after receiving it (as “recently serviced”) and opening it to view the movement, I noticed some large bits of crud in the movement (hard to see here, but they were there).



On the Timegrapher it was very erratic so I thought it could do with a service and after my last job (Seiko Chronograph) I thought I deserved something simple. So off to the bench it goes.
My reference for the service is TM 9-1575, the US Army manual for watch maintenance in the 1940s. My copy is rather fragile to use on the bench so I’ll be using my PDF copy which can be found here.


Not many fancy tools required for the task of disassembly, just these will do.



So off we go.

 

First, the caseback is removed and the movement holding screws are undone.



And taken out.



After removing the front bezel/glass the movement can be pushed out and set on a pad to remove the hands (camera problem so no shots of that).



The three dial screws are backed out.



and the dial is removed from the movement and put in a tray for security.



The small gold dial washer is removed from the centre and then the canon pinion is pulled off. I had to use a stainless washer to give the puller more purchase and protect the parts beneath.



And what’s this? Another dial washer? Recently serviced? Hmmmmmm……..

 

Next I checked again that the mainspring was fully wound down by releasing the click and letting the last gasp unwind.



Then I could unscrew the hairspring stud screw and separate the hairspring from the balance cock and remove the balance cock.



And then remove the balance and hairspring assembly. The pallet bridge and pallet assembly are removed at this step as well.



Next the balance cap jewel and regulator assembly are stripped so that the jewels and parts can be cleaned properly.



I noticed that there was some strong attraction between the steel parts of the regulator. How could a recently serviced watch become so badly magnetised? That may explain some of the Timegrapher results.

 

With the delicate parts safely stored, it was time to remove the ratchet wheels and the click. It’s got a spring so I took no chances and held it with a stick so it would vanish.



Then the second winding wheel could be held with a plastic stick and the screw removed.



The three barrel bridge screws are undone and the bridge removed.



The train bridge is also removed so that the mainspring barrel and all of the train wheels can be removed. The blue shipping lever screw can also be removed here. @Canuck



Another spring! This clip is holding the winding arbor, clutch and pinion, I didn’t know how “springy” it was so into a plastic bag so it didn’t go ping.



Now back to the dial side. The setting cap spring and winding/setting parts can be removed. But there’s another spring under there (near the point of the tweezers….).



So it’s bag time again



Now that the major parts are all off and everything is safely stored, I just need to remove the cap jewel plates, inspect everything and get the parts ready for the cleaning machine.

 

"The watch has been serviced and a new mainspring fitted" was the seller's description.

I tend to take all of these claims with a grain of salt unless there is a recent invoice from a reputable servicing entity.

So I wasn't shocked when I opened the barrel to check the mainspring.



I must have had a premonition, maybe we do have spidey senses.

https://omegaforums.net/threads/and-what-did-you-buy-today-watches.8930/page-423#post-656414

 

So far, so good. But always let the power down while to movement is still in the case. Simpler, and safer.

 

I had let the movement run down for a few days but figured that there would always be a bit of energy left.

And after a ballistic 8 day Ansonia clock spring experience, I treat any spring with care and respect.

 

Have you mentioned your findings to the seller?

Also, nicely done----maybe this should be a sticky?

 

Too late, more than three months ago, and it may not have been their fault. Maybe .

 

Maybe write it with the assumption that the seller did have it serviced and you're cautioning the seller against using that watchmaker again?

Thanks for posting the story and pictures!

 

The mainspring in this model is held in the barrel by a small tab on the tail of the spring, that tab engages in a slot in the roof or the barrel.

When the "new" mainspring was fitted it wasn't a Hamilton item but a generic one with a bent back tail that would engage in the notched wall of a different style of barrel

So to stop it whizzing around because it's not a notch wall barrel, a pin was pushed into the barrel to hold the spring.

I didn't think that @STANDY did watchmaking in his younger days

 

As mentioned before only case I open has beer in it and a fishing reel with 1/10th the moving parts is my limit.

 

So you weren't the butcher?

 

Why do butchers get that much stick.
If it was butchered it would be cut up nice and evenly and presented neatly on a tray.

 

That's a nice 992B. Early one too (C17713 - 1940). I have one with the same dial but more recent (C97530 - 1943). Your thread is very instructive. I plan to eventually service mine. Thanks!

 

Pretty pissed off right now .

I started inspecting and checking things today. I took the lower pallet assy/escape jewel plate off to check the plate jewels. No problems, and the jewels in the plate looked fine if a little dirty.

Then I took the lower balance jewel plate off.

Aaaaaaargh!

Instead of a nice clear jewel like in the upper plate, there was a pink cap jewel from a wrist watch under the plate. WTF!



I'd noticed it before but as I'd seen both pink and clear jewels in these plates it didn't concern me, but why?

I then checked the plate jewel and got another nasty surprise.



The jewel has been pushed into the plate for some reason (to make room for the "added" jewel?).

Comparing the jewels shows that there is something amiss, they should all be similar.



Turning the plate over I now notice the balance jewel (red circle) has had it's surround ground down .



What's going on? I decided to have a look at the balance assembly and there I found the reason.

It appears that the watch previously suffered from a broken pivot. Not a big problem, just fit a new balance staff and all is well.
But....................
It also appears that the "watchmaker" didn't have the correct balance staff and couldn't be bothered waiting to get one in or pay for one.
So it looks like he's grabbed "a balance staff" and McGyvered it together, but "fuck me" he goes, "it's too f*k'n short, I know, I'll push the jewel in to stop the end shake and use another jewel to take up the slack".

Here's a shot of the bottom of the balance assy.



It isn't until you get up close you see the true horror.



The roller must have been a bit loose so he melted the whole lot together with shellac.



So now, besides being monumentally pissed off, I'm at a crossroads.

Option 1. Just finish the service, put it back together and take a "lesson learn't" pill.

Option 2. Source a new lower plate jewel and cap jewel plate and complete balance assy (or all the parts) and rebuild it.

Going option 1, my heart just wouldn't be in it.

Option 2 would be nice, but I can't re-use the hairspring as I don't know how much the collet has been f*cked up so a full balance assy would be needed. I also don't have a jewelling tool but I suppose I could use my staking set.

So I need parts that are pretty well hard to get in Australia, so this Option is much more of a challenge.


Any feedback (big hugs etc.) and suggestions/comment/advice are welcomed.




I think i'll go to the garage now and find something to hit with a big hammer.

 

That sucks.
If you go with option 2 (by purchasing with ebay, Casker, etc.) and a US seller doesn't ship to Australia, I can perhaps assist in getting the parts to you.

 

I'm a bit calmer now.

The hunt is on.

And the offer of assistance is greatly appreciated, and it's also what makes this a great forum.

 

This watch appeared to have been serviced by the "low bidder". Problem is, that people who go for a cheap repair only get half a repair, generally done by someone who is only capable of half a repair! The 992B was called "the watchmaker's watch" because it was so much simpler to service than it's predecessor, the 992. Even so, this one appears to have been serviced by a Neanderthal! Too bad!

 

OTOH, since literally a million of these were made, finding replacement parts should be relatively easy. Somebody once noted the 992B is the most precise mass-produced mechanical item ever made.