On My Bench - Omega GSTP Pocket Watch - Caliber 38.5 L T1

JimInOz · Mar 27, 2019

I recently received a couple of pocket watches from a very trusting member who asked if I could do anything to resolve the problems with them. One was a well used Omega GSTP ex military watch, the other a nice little Elgin. Being an Omega fancier I thought I'd start on that.

First thing is a visual inspection, and this one showed that it hard worked hard. Next was a quick timegrapher check to see if anything obvious stood out. That didn't go well as it wouldn't run in any position longer than a few seconds, so straight to disassembly.

With the caseback off I first removed the balance assembly and was surprised at the amount of oil around the place. Although hard t see here, let me assure you there was a LOT!

With the balance under a microscope, it wasn't hard to see a problem. Like may watches lacking shock protected balances, this one had a broken balance staff pivot.

Even if the pivot was fine, I don't think this watch would have kept time anyway. Hairsprings must be scrupulously clean to function properly, and this one had enough oil trapped between the spirals to lubricate the whole watch!

Now that we had identified a culprit, it was on to complete the tear down. No other major surprises, other than evidence of amazing amounts of oil.

Next was the barrel and mainspring, which once again didn't disappoint with the amount of oil 😁.

Finally, all of the parts were ready for inspection to see if there were any more secrets.

Some of you may notice the mainspring. This caused me to consult my mentors for advice which you can see here.

So a new mainspring and a new balance staff were ordered, and so we continue.

JimInOz · Mar 27, 2019

Well, after my worries about the new mainspring were unfounded, I decided to change it out for a bit of relaxation.

Because there was evidence of manufacturing swarf and bits of holding ring floating about, I decided to pop the spring out and clean it properly. I cleaned the barrel, cover, arbor and new spring and got ready to fit it.

Here it is on the bench next to the original, "some difference eh!" (as some members here would say 😉).

And now lubricated, re-wound and fitted to the barrel and all buttoned up. Sorry there are no step by step pics, I got a bit absorbed with the task.

Anyway, here it is, ready to power the watch for another 70 years or so.

JimInOz · Mar 28, 2019

GREAT!
🤬

My worklight has just decided to crap itself 😡.

I thought it was just my eyesight getting worse but when the last tube went I was a bit relieved to know it wasn't me 😁.

Oh well, off to the lighting store tomorrow morning.

JimInOz · Mar 29, 2019

Went to Bunnings and picked up 3 new Nelson T5 fluro tubes for my task lamp. Got home and went to fit them, first two out of the packet fitted fine and lit up, went to fit the last one and as I took it out of the packet, I noticed it was a Sylvania tube 😵‍💫.
WTF!
It was dusty and not a brand new Nelson tube. Just for laughs I tried it and sure enough it was dead.

So! Back in the car and drive back to Bunnies, stand in the returns queue, explain it all to the nice young girl, go and get a correct item, notice another scruffy packet in the fixture so I pulled the tube out and sure enough it was a Sylvania in a Nelson packet. I took that one back to the nice young girl (she was very nice, wish I was 50 years younger 😉) and gave her the dud one. She said it happens all the time. Pricks buy something like a fluoro tube, take it home, swap it out and then return the dud one in the original packet with a lame "my wife bought the wrong size" or other bullshit. All for a few bucks FFS!

Anyway, after I fitted the new tubes I found one of the ballasts had crapped itself, probably that damn dud tube that did it. Still got two good working tubes and a "spare" though so all is not lost. Maybe a new LED task lamp 😁.

Well, that was my lost day, sorry Geoff, be back into it tomorrow before I head off to footy. Go Bombers!

mac_omega · Mar 29, 2019

I am impressed by your equipment and your order 👍

JimInOz · Mar 29, 2019

mac_omega
I am impressed by your equipment and your order 👍

It would have been better if I'd used a dust sheet over the bench before I started pulling the lamp apart.

Now I'll have to vacuum and use a dust catcher like a busy housewife to get my bench clean again!
I'd ask Annie to do it but her response would be "you made the mess! You clean it up!" 😁

omegaswisst · Mar 29, 2019

JimInOz
Go Bombers!

Bit of a poor performance last week against GWS 🙁. Let's hope they pick up against St Kilda.

Nice setup 👍

verithingeoff · Mar 29, 2019

Your first real match comes on April 13...Go Lions go woooo

verithingeoff · Mar 29, 2019

Your workshop looks brilliant Jim, I used to have a nice workshop in the garage but I have bad arthritis in both hands and wrists so the mill, lathe etc had to go. Any engineering I do these days happens in the 1/2 sq metre of my desk!

JimInOz · Mar 29, 2019

verithingeoff
Your workshop looks brilliant Jim, I used to have a nice workshop in the garage but I have bad arthritis in both hands and wrists so the mill, lathe etc had to go. Any engineering I do these days happens in the 1/2 sq metre of my desk!

I feel your pain Geoff (one knee and one elbow every day) but so far my hands are OK. Probably shouldn't have ridden motorbikes and played footy like I was a champion all those years ago. Still love to get on the beast on a nice day and ride for an hour or two. More relaxing than yoga I reckon.

Back on topic.

Part of the job of doing a good service is to inspect the parts before cleaning, and then inspect them after.

As I mentioned earlier, this watch has seen an inordinate amount of oil applied to it, and excess oil attracts dust and "bits".

Here's a shot of one of the jewels before cleaning. Is it just crud? Or something more sinister?

After running the plates and bridges through the ultrasonic and the cleaning machine, you can inspect again, and this is where the real problems become obvious.

Now that all is pristine, we can see a chipped upper fourth wheel jewel. If it's left it will affect the performance of the watch, and more importantly, will act as a little scraper, taking microscopic shavings of the forth wheel pivot and producing bits of metal and jewel to get into the movement. (Worst case scenario I know, but it isn't unknown).

Not having access to the specific jewel for this position, and my home made "jewelling tool" probably not accurate enough to set end shake, I sent the main plate, fourth wheel and train bridge to a well known watchmaker to see if he could do me a favour.

We shall see what happens.

verithingeoff · Mar 29, 2019

He should do you a decent job, I've bought enough watches from him!

Archer · Mar 29, 2019

JimInOz
Now that all is pristine, we can see a chipped upper fourth wheel jewel. If it's left it will affect the performance of the watch, and more importantly, will act as a little scraper, taking microscopic shavings of the forth wheel pivot and producing bits of metal and jewel to get into the movement.

You should check the fourth wheel pivot, as this damage likely didn't happen yesterday, but has been there for some time. In fact you should be checking all the pivots under the microscope if you haven't done so already. If they are worn, then depending on condition you can use the Jacot tool to burnish out light scoring, repivot, or try to find new...

BTW that's an easy jewel as it's a regular press fit style. The bezel set jewels (a.k.a. "rubbed in") are the ones that are a real pain to deal with, and nearly impossible to find replacements for. That's one reason I no longer accept US made pocket watches for servicing - they almost always have a bunch of broken jewels inside.

95% of the skills you need to have as a watchmaker can be learned on a simple 3 hand movement. IMO people shouldn't even move on to autos (let alone complicated watches) until they have really mastered the issues you find in a simple watch...actual watch repairing, rather than just parts replacing. Glad to see you rectifying this, because many (including some "professionals") would simply let this go...

And I do understand lighting problems - I had the frame on one light snap a few years ago, and without a light I can't work to earn a living. I ended up ordering a new light, and then setting up a bunch of lamps from a light tent kit that I had for photography as a temporary light source. I have since replaced the lamp that I bought after the failure (it was also fluorescent) and went with a very nice LED lamp. It turns on instantly, doesn't throw off nearly as much heat, and has far less UV output (safer for someone who has their hands/face under the lamp at close range for hours each day). Now that fluorescent is a back-up!

Cheers, A

JimInOz · Mar 31, 2019

Archer
You should check the fourth wheel pivot, as this damage likely didn't happen yesterday, but has been there for some time. In fact you should be checking all the pivots under the microscope if you haven't done so already. If they are worn, then depending on condition you can use the Jacot tool to burnish out light scoring, repivot, or try to find new......
Cheers, A

Understood and agree Al. Problem is that, while I have a microscope and can find scored pivots (none so far except for the fourth wheel) I don't have a Jacot tool to burnish/polish them (finding a complete one is a rarity).

I had considered using a lathe (uncoupled hand turned) and a burnisher from a screwdriver blade and self adhesive 3.0µ polishing film. I'm still trying to figure out how to support the free end so I don't create more damage than I'm trying to fix.

Any suggestions welcomed.

Archer · Mar 31, 2019

JimInOz
Understood and agree Al. Problem is that, while I have a microscope and can find scored pivots (none so far except for the fourth wheel) I don't have a Jacot tool to burnish/polish them (finding a complete one is a rarity).

I had considered using a lathe (uncoupled hand turned) and a burnisher from a screwdriver blade and self adhesive 3.0µ polishing film. I'm still trying to figure out how to support the free end so I don't create more damage than I'm trying to fix.

Any suggestions welcomed.

Is it a watchmakers type lathe, and do you have collets? If so, you might be able to grip one end of the wheel (not by the pivot, but possibly by a larger diameter) and then polish the pivot. I've done this before (when I didn't yet have a Jacot tool) and I have used diamantine powder mixed with oil to form a paste, and then polished the pivot by picking up some of that paste on a cut piece of peg wood, and then applying that to the pivot in question.

Ideally holding the wheels with a stepped collet designed to accept the larger part of the wheel would be better than having a whole bunch of mass hanging out from the collet, but you would have to buy a set or two of those stepped collets to cover the range of wheels you typically deal with.

Make sure you thoroughly clean the wheels after though as you don;t want any abrasive particles left behind.

Of course burnishing will give better results, and will allow you to control the diameter much better, but if you don't have that set-up and you have a really rough pivot, sometimes smoothing it out a bit can help.

Cheers, Al

JimInOz · Mar 31, 2019

Thanks Al, I didn't even think of stepped collets.

I have a suitable lathe.

And an assortment of parts, let's see what I can find.

And voila! A set of stepped collets.These were the best of the bunch I had.

kpaxsg · Mar 31, 2019

Hi @JimInOz Do you repair clocks? 😀

JimInOz · Mar 31, 2019

kpaxsg

Hi @JimInOz Do you repair clocks? 😀

I have been known to 😉.

Archer · Apr 1, 2019

JimInOz
And voila! A set of stepped collets.These were the best of the bunch I had.

I think you are all set then...

JimInOz · Apr 2, 2019

Self-explanatory photo.

Peg wood stick, oil mixed with 0.5µ diamond paste, 5X loupe.

JimInOz · Apr 6, 2019

Just finished re-assembling the balance cock assembly after all parts (cap jewel, regulator, end-piece bolt, stud screw and cock) had been cleaned and checked.

The stud screw is TINY!
Only took three tries to get it in though so I'm happy with that, I was about to walk away if the third one fell out again.
Here it is next to a 0.6mm screwdriver blade.

On My Bench - Omega GSTP Pocket Watch - Caliber 38.5 L T1

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