Servicing my Hamilton 992B Railway Special - Model 2 - 1947 - Pt 2

My replacement movement arrived from Denver yesterday and aside from a lot of dirt/fibres/old lube it appears to be in reasonable condition except for an incorrect setting lever screw (red arrow). The balance spins freely and has hardly any endshake or sideplay.



Jewels all look fine, although rather dirty and will need a good clean. The Centre Wheel jewel.



The screw heads are in good condition and show slight evidence of past work, and a lot of dirt. This is the ratchet wheel screw.



The dial side again shows a lot of dirt and old lube (or verdigris?)



A close-up of the sub-seconds pivot and surrounds.



Next step is to put it on the timegrapher to see how it performs prior to servicing.

Does anybody know the lift angle for this caliber?

@Canuck ?

So a very basic timing test.

I'm only testing in one position, crown up, which I assume to be the normal state for a pocket watch.

Using the standard settings I see a bit of noise, decent amplitude, good beat error and losing 17
seconds+ per day.



Changing the lift angle to 36°, a figure from the internet, shows much the same, but with lower amplitude.



Now that I have a rough baseline I'll let the movement run right down to get an idea of power reserve and then I can start disassembly.

Cleaning and inspecting after I put the mounted balance through the cleaner.

CURSES!!!!

Cracked lower balance jewel. 😡



Anybody have a spare?

Another learning experience. Setting a jewel with a staking set.

OK, the cracked jewel has been pushed out with the aid of my staking set, I hope that was the hard part 😉.



The lower pivot of the balance staff had some scoring so I've ordered a new one as well as the replacement jewel.

Another wait begins.

Questions from me:

Does it matter what side of the plate I press the jewel in from?

I see a very slight chamfer on one side of the jewel hole, so I assume that is to assist seating and pressing.
The jewel housing also has a slight chamfer on the sink side wich also support pressing in from the bottom (dial side) of the plate.

For depthing/end shake checking, is it OK to do it with just the balance staff and not a complete balance?

OK, so where did we get to. We had the replacement movement all cleaned and ready to assemble but less one balance jewel. Well that finally arrived so I compared the two before going too far. The old jewel was 1.6mm dia and the new one ws 1.61mm dia, with the reading flicking to 1.6mm so I was happy we had the right one and ready to install.

Well I had my old staking set, and selected a correctly sized stake and a flat anvil.
But it wasn't really meant for jewelling, it would be easy to push the jewel too far.



So it was out to the workshop to come up with a solution and create a jewelling attachment for my staking set.
Some nice hardwood cut to size and shaped and a pine block with index pins from MS rod would hold the staking tool.



Put it all together and I have something by which I can press a jewel, and when needed, adjust the depth using the "micrometer stop" (nut and bolt assembly" and an old DTI to give me a rough indication of how much movement is being made when pressing.

Put it all together and I was ready to go.

First, the jewel was placed on the plate in the correct orientation.



And then pressed to first depth using an oversize stake and flat anvil.

The cap jewels were then replaced on the plate and the balance cock and the balance staff was fitted to check for end shake. There was a bit too much end shake so I got a smaller stake and pressed the jewel down a touch more and checked again.
It was almost there on my third try when I heard a dreaded "click" when I removed the balance cock!
I'm a lot calmer now but I was really p*ssed off and almost decided to bin the whole lot, anyway I went back to it the next day and had a look at the original balance staff. The scoring wasn't too bad so I cleaned up the pivots on the lathe and put it all back together. Now I could start assembly and test the train for backlash as previously described (and as mentioned by Al, this time before oiling).

More later, I have to start dinner for my Darlin' who'se on the way home from a hard day at work.

OK, dinner is all ready to go so I'll wrap up to where I'm at now.

After stripping back down and treating the escape wheel and lever pallets with epilame, I oiled all of the cap jewels and fitted them. This is the lower cap jewel ready to fit on the balance cock, you can see the drop of oil in the centre (hope it's not too big).



The balance cock was placed over the cap and all things tightened up. I think most of the oil was drawn into the balance jewel by capillary action so that huge drop of oil is all it's going to get.

The rest of the components were then assembled, all of the other jewels oiled and the watch was run for an hour before oil was applied to some of the escape wheel teeth and then the movement was left to run in overnight.

The first run on the timing machine set at LA of 40 degrees produced:

PU= MINUS 29 SPD BE = 0.3MS
PR= MINUS 31 SPD BE = 0.3MS
PD= MINUS 33 SPD BE = 0.1MS
PL= MINUS 31 SPD BE = 0.3MS
DU= MINUS 0 SPD BE = 0.3MS

(PU, PR etc is same as CU, CR).

Amplitude was fairly consistent between 270 to 290 degrees.

The big difference between vertical and dial up positions is a bit surprising even though I'm aware that all of the pivots are now riding on the jewels, maybe somebody could comment?

Tomorrow I'll do some adjusting to bring it into a better rate at crown up as this it the position a pocket watch would spend most of its time at.

Sorry, didn't explain that too well.
I think I must have twisted the balance cock as I was taking it off, getting it away from the studs had been a bit sticky and on the last effort I must have got a bit ham fisted.

All part of the learning experience, but I still kick myself.

TIP: The balance staff is much easier to manage when it's in the middle of a big wheel/spring/roller 😉.

😲

Great educational tool!

Thanks very much Chris.