Dissection of the Omega 2500B Co-Axial movement

[J!m 289]

So, a while ago I took a chance on what might have been something other than advertized- an Omega 2500 movement, for short money.

 

Well, the good news is it was infact genuine; the bad news is that it aparently was swamped in the watch, and had damage and corrosion.

 

The other day, I decided to dissect it and see what was/is wrong with it.

 

 

So first I took the auto winding bridge off. No big deal, and I found that is actually in decent condition. Filthy- but not broken. It winds smoothly and quietly in both directions, but needs a clean and lube job. Moving on...

 

 

Next is the gear train bridge- remember I just wanted to tear this down enough to assess the parts and figure out what would be involved to make this tick again... (don't forget to let down the mainspring before you pull the bridge!)

 

 

 

Now we can see the gear train- pull it out carefully- in order (these parts are so tiny it is amazing)

 

There- those are all fine, so the problem is deeper (other than the balance wheel top jewel missing)

 

 

That looks like an escape wheel under there... And it is! BUT, it is one of two escape wheels (this is a Co-Axial!) so it goes together a bit differently than a conventional movement, and gave me a scare when I was re-assembling it (I found an Omega drawing of the escapement on line, link posted below)

 

http://www.google.co...ved=0CFMQ9QEwBg

 

Now the balance wheel bridge has to come off- this was not easy because the hairspring is corroded, or has corrosion on it (from the main problem, discovered next) and it did not come along quietly! But I did get it out without destroying anything to get to the meat of the problem...

 

 

In the photo above, you can see me pointing at what loks like nothing, but the hacking lever is next to the tweezer point- I wanted to remember which way it was oriented. But, if you look where the balance wheel was, you can see a dark spot- that is (was now) one of the screws that hold the escapement bridge in place. It is pure rust. I think the rust from this screw deposited on the other parts and stained them. I have no way to clean them properly, so this was re-assembled, my assessment added, and it is back on the 'Bay for a better watchmaker than I am!

 

 

Better view of the dark blob... It took some work to clean the screw slot so I could get it out! But I got it out and found the pallet fork was OK but also stained by rust.

 

 

The second escapement wheel is still seen, but it comes right out too.

 

Overall, the movement is is good shape, but needs a balance wheel (maybe just a clean), hairspring, balance wheel shock/jewel THOROUGH cleaning, lube and adjust and it would be good for several years.

 

Anyone interested in tackling this beast, search for the Omega 2500 B on eBay... I need easier stuff to fix!

 

I hope you enjoyed the write-up!