Broken Case Screw Omega 30T2

[gaber]

Hi all!

I grabbed an Omega Ref. 2272-3, circa 1944, off ebay, being sold as defective because it does not wind up.  The watch movement was not pictured in the ad (!), but the guy said it was from his personal collection.  I'm still quite green, but I was in the mood for a little adventure, so I took the gamble.  I really like Omega.  I probably paid too much.  :).

When I received it in the mail, I was happy with the cosmetic condition, although I noticed signs of previous struggles to open the case back (bit of damage around the groove).  Here is a shot of the face:

 

Note the Portugal hallmark on the upper left lug -- neat!  There is strong patina, but the shiny silver numerals and nice hands (perhaps NOS replacement at some point?) make it quite attractive to me in the light.  There is a small rattle when I turn the watch, so something is a bit loose.  Anyway, I gingerly approached the task of opening it myself and managed to finally get a look inside!  Here is what I found:

I don't have a seasoned eye for looking at movements, but it seems OK to me!  Blue hairspring, hmm, I'll have to look that up.  Bit of some gunk on the ratchet and crown wheels.  I guess it's corrosion, but it comes off a bit with pegwood.  With a little shake, the balance gets going, and the seconds hand will track forward a few seconds, before the movement comes back to a rest.  I have not taken Mark's third course yet on fault finding; I will probably do this before I really dig into this one.

BUT, the main thing I noticed was that one of the  case screws was missing (upper right in this photo; bottom left was removed by me).  However, as I stared, it seemed that the screw hole was actually not empty!  Indeed, it seems that the missing screw is actually half still there, unfortunately, broken off and sitting inside the hole.  (Starting to make more sense why the owner wanted to part with this watch...)

Now I have read about various removal methods for broken screws, but they all seem to require that the movement is removed from the case.  I believe that, for 30T2, the screws hold the case in with friction generated by outward force they create inside the case -- I read this somewhere.  With the one good screw removed, I do feel a tiny bit of play in the movement, but it is not jumping out.

So my question is really this: any ideas of how to proceed?  Perhaps a clue about how to safely remove the movement (with the one broken screw still applying pressure, keeping it in place).  I have tried some gentle prying with pegwood around the edge of the movement, but no progress there.  Do I have to open it from the front and push on the watch dial?  YIKES!

Thanks very much, and sorry if I made this too long.

-Gabe

 

[watchweasol]

Hmmm   judging by the size of the back and the dial size this looks like it comes through the front.  Check round the bezel for indications of prior removal. If I am correct there should be a small nick to insert a blade for removal.

[gaber]

2 minutes ago, watchweasol said:

Hmmm   judging by the size of the back and the dial size this looks like it comes through the front.  Check round the bezel for indications of prior removal. If I am correct there should be a small nick to insert a blade for removal.

Indeed, the bezel has signs of removal (near the location where there are signs of caseback removal).  So I pop off the bezel, the glass, and then I can push on the movement to slide it out the front?

[watchweasol]

Hi  that should be the case but be careful, removing the broken screw, try to unscrew it with a needle point it may be loose enough to un wind  hopefully   cheers

[gaber]

19 minutes ago, watchweasol said:

Hi  that should be the case but be careful, removing the broken screw, try to unscrew it with a needle point it may be loose enough to un wind  hopefully   cheers

Thanks, I will give it a try!

[gaber]

Hi again, watchweasol. 

You were right!  The movement came out very easily through the front.  Here is the dial side:

The seller simply said it did not wind, but what I found was that it was actually fully wound.  I removed power from the mainspring, and found the winding mechanism seems buttery smooth and working flawlessly.  While I was fiddling with this, I noticed that when i turned the crown to push the clicker almost fully over, the watch sprang to life and continued without stopping. 

Interesting!  The watch stops again when I remove the tension from the crown.  This seems like an important clue.  I am feeling elated about this purchase right now.

Regarding the broken screw.  The end is visible on the other side:

  I fiddled around with a needle and a screwdriver, but it didn't seem to move.  Perhaps I haven't used the right technique.  From what I understand, one should put the tool in at an angle, and use the uneven surface of the broken screw to exert the torque.  Anyway, no luck yet with that, but the screw end is so prominent... perhaps I could grab onto it somehow.

Maybe I should leave the screw alone.  As far as I can tell, it does not seems to serve any purpose, given how the movement is installed into this case.  But....it would feel nice to pull it out!

[HSL]

I’m a sucker for gadgets and just before summer vacation I took the regular look at AliX to see what the boys had come up with. To my surprise I found this contraption to remove broken screws with.
I got even more surprised when it actually worked. One just takes the appropriately sized carbide grabbers. Fixed on one end and the ability to tighten on the other. When positioned correctly I just rotated the movement and the screw came right out.

Think it was so cheap so it was worth to order just incase it worked.

[gaber]

19 minutes ago, HSL said:

I’m a sucker for gadgets and just before summer vacation I took the regular look at AliX to see what the boys had come up with. To my surprise I found this contraption to remove broken screws with.
I got even more surprised when it actually worked. One just takes the appropriately sized carbide grabbers. Fixed on one end and the ability to tighten on the other. When positioned correctly I just rotated the movement and the screw came right out.

Think it was so cheap so it was worth to order just incase it worked.

Hmm, looks like it operates just like the Bergeon tool (30209).  Do you have a link?  What was the cost?

[HSL]

7 minutes ago, gaber said:

Hmm, looks like it operates just like the Bergeon tool (30209).  Do you have a link?  What was the cost?

https://www.aliexpress.com/item/4000117442092.html?spm=a2g0s.9042311.0.0.c9994c4dyhBvfk

[gaber]

38 minutes ago, HSL said:

https://www.aliexpress.com/item/4000117442092.html?spm=a2g0s.9042311.0.0.c9994c4dyhBvfk

Quite a deal!  Will have to wait for the shipping from China, but I am tempted ...

[gaber]

I thought I would follow up on this, since I bought one of these inexpensive screw removal tools.  I used it today, and though I managed to get the screw out, I spoiled the area around the screw hole a bit with scratches.  This is partly because the tool has a misalignment of the two bits that are supposed to apply opposing force on the broken screw.  See here:

O

 

Other than this significant defect (which maybe I could correct by bending the frame), the tool seems fine.  Everything else fits well and seems to perform correctly.  More photos:

[rodabod]

Those tool bits are odd looking. Maybe cob mill bits. That misalignment is shocking!

Glad you got it sorted. 

[HSL]

That alignment didn't look good. I had to go back and look at mine too.  And sure enough, when choosing another pair of tools, it got misaligned in nearly the same way.
The I had to investigate the reason for this, since when one push a straight tool through both holes one can see they are aligned.
But the hole where the tool goes seems to be reamed in an odd way. It seems instead of having a straight broach they used a conical one which gives a small bevel in the front and back of the hole and a nice pivot in the middle. So, when one fastens the tool bit with that screw in the back it rises a bit in the front and the centering is lost.
One can see that on your picture too.


The front toolholder is centered so a dirty fix for this problem is to fasten the one with the screw on the top after you pushed it onto the screw. But the correct fix for this is to drill a new hole and fit a new straight brass bushing in the hole.

[gaber]

Hi HSL, thanks for the tip.  On mine the left bit has some play and I can push it up by inserting a bit of pegwood to help the alignment.  Not a great fix :).  Ah well, the thing works enough to serve some use!

[Poljot]

I wonder if Locktite was invented in 1930s not in 1950s as removing the screws from my 30T2 Omega movements was real challenge. All movements appear to be "brand new", some may even call them virgin, but they were screwed (= over torqued), and some case screws (Omega 2708 & 2709) snapped.

Using Bergeon 30209-like tool was a good start, but i ended up using my trusted K&D Inverto staking tool to apply pressure on both ends of the broken screw and then rotate the plate. Happy End!