Vintage Omega Seamaster--back removal--solved

[LittleWatchShop]

Before I screw this up, I am coming to seek advice...yet again!!

I think this is a snap back, but it is on tight.  I have only tried to test with a razor blade.

 

 

Found this on the NAWCC forum.  It is a snap back.

[watchweasol]

Hi LWS  this is a grand old watch, have a look round the edges especially near the lugs for entry signs. I have known some snap backs be bloody tight , but check all avenues first sticky ball ( screwback) or the nut and super glue method as there is no slots       cheers

[LittleWatchShop]

Got it.  Almost appears to have been glued in.

Omega Cal 471.  It is running but needs a lot of dial work and new hands.  May need a center wheel for the sweep second...might be a challenge.

[watchweasol]

Hi  a nice old movement  well made. The case back looks grotty, no wonder it took a bit of getting off. Attached a sheet that might be useful.    cheers

342_omega 471 (1).pdf

[KarlvonKoln]

Even without the glue, I find the snap backs on old Seamasters are awfully mucking tight.  I used an X-acto knife to open the last one I worked on.  I don't like doing that, as I'm always afraid I'll slip, but I'm starting to develop a way of holding it that works and feels steady.  I haven't stabbed myself or gouged the case yet.  But I still want to get a thinner kind of case knife and sharpen it up a bit for watches like this.  Something easier to use maybe.  
I have to say though: the Glycine Compressor I have right now is the tightest snap back I've worked on by FAR.  If I hadn't already known full well that it was a snap back, I'd have sworn it must be a front loader.  It's almost like that back was welded on.

 

[LittleWatchShop]

24 minutes ago, KarlvonKoln said:

Even without the glue, I find the snap backs on old Seamasters are awfully mucking tight.  I used an X-acto knife to open the last one I worked on.  I don't like doing that, as I'm always afraid I'll slip, but I'm starting to develop a way of holding it that works and feels steady.  I haven't stabbed myself or gouged the case yet.  But I still want to get a thinner kind of case knife and sharpen it up a bit for watches like this.  Something easier to use maybe.  
I have to say though: the Glycine Compressor I have right now is the tightest snap back I've worked on by FAR.  If I hadn't already known full well that it was a snap back, I'd have sworn it must be a front loader.  It's almost like that back was welded on.

 

I used a safety razor blade.  It is a technique I have used before.  What I do is slip it in the gap and rock it up and down.  I do this on the sides (not the lug ends).  Sometimes, I break the blade but that is OK, I have plenty.  There is that fear, as you say, that I will slip and damage the movement or cut myself--not sure which is worse!

[KarlvonKoln]

I have made knives before, but I was borrowing a buddy's forge back then, because I don't have my own.  But now I have this idea for a new case knife - slightly smaller and thinner blade, very slight hollow grind, much sharper than a standard case knife, with same rounded tip (of course).  If I can borrow the use of someone's forge, I may make a prototype  knife, and then pick up some old cases with the tight backs and try it out.  Might have to make a few to adjust the design.  But I'd like to have something I feel more at ease about, rather than just sticking a wicked-sharp brittle blade into the tiny crack of an expensive case.  
I will say this though - I like the idea of using super glue to put a stick or lever or something onto the case back and then just yanking it off.  That's bloody brilliant!  BUT...it did not work on my Glycine Compressor.  Thus the need for a backup plan.  I ruined a few X-acto knife blades on that watch before I got it open.
I'm always open to better ideas like that. 

[JohnR725]

On 7/13/2022 at 1:30 PM, LittleWatchShop said:

Got it.  Almost appears to have been glued in

there was a technical problem with some back gaskets a while back. I've seen it with Omega watches the caskets disintegrate sort of. Rather than getting a hard and brittle like they normally would do they turned the glue. Well maybe more like tar sticky hard to clean a half. I had seen it originally only with Omega watches but then noticed gaskets that I had in packets some of them had just disintegrated. That must've been a specific time span were somebody screwed up on the gasket formula and it rippled through whole bunch of watches. You don't seem to see it as much as he used to.

[LittleWatchShop]

I am finally servicing this watch today.

I use L&R fine watch cleaning solution in an L&R spinning machine (not US).

What precautions should I take regarding the automatic wind components?

[LittleWatchShop]

Specifically, this reverser assembly.  How to clean and how to oil.

[JohnR725]

4 hours ago, LittleWatchShop said:

What precautions should I take regarding the automatic wind components?

yes that's an interesting question.  then you read my mind as I needed a picture but I also did a  search in my computer and I found this.

then you make out in that I did a search of my computer looks like I actually scanned this versus acquiring it from who knows where you get a service bulletin. Unfortunately you have to figure out some of the lubrication on your own as so much for lubrication standards throughout time of servicing watches.

Omega 470 500.PDF

[LittleWatchShop]

LOL...JohnR725, never cease to amaze me.

[canthus]

This is for the 551 but very similar to the 471 and many parts carried over from 470 series to 550 series. It shows a similar reverser setup.  You may find it helpful for serviving movement as well.

When i serviced my 552 I tried to make a tool to turn the centre nut but gave up.  I immersed the unit in lighter fuel and give it a good whiz in the US cleaner. To oiI, I managed to prise it open a enough to get a fine oiler in and apply oil to the inner gears. Its run for 4 years and worn daily, so must have worked ok!

Omega-551.pdf

[LittleWatchShop]

4 minutes ago, canthus said:

This is for the 551 but very similar to the 471 and many parts carried over from 470 series to 550 series. It shows a similar reverser setup.  You may find it helpful for serviving movement as well.

When i serviced my 552 I tried to make a tool to turn the centre nut but gave up.  I immersed the unit in lighter fuel and give it a good whiz in the US cleaner. To oiI, I managed to prise it open a enough to get a fine oiler in and apply oil to the inner gears. Its run for 4 years and worn daily, so must have worked ok!

Omega-551.pdf 6.38 MB · 0 downloads

On the 471, there are holes in the top gear that are not shown in the document you sent.  Maybe they added those holes for oiling access. I have the watch assembled now with no attempt to clean that one part, nor oil it.  I will ponder.  Still waiting on a crystal to arrive and am fixing the dial today, so I have some time.

[JohnR725]

2 hours ago, LittleWatchShop said:

On the 471, there are holes in the top gear that are not shown in the document you sent.  Maybe they added those holes for oiling access. I have the watch assembled now with no attempt to clean that one part, nor oil it.  I will ponder

The critical thing on the Omega self winding watch is and it goes by differing names but the reversing wheel. Usually on the later watches it's one unit all sealed up. Yours looks like it disassembles which is easier. Even though the later ones supposedly can be taken apart they require special tools that nobody has.

If you have the the sealed up variety then you have to lubricated and a proper fashion or you will regret it. There is actually a lubrication for lubricating it properly. This tends to be the problem with the automatic watches is whatever the reversing mechanism has to be lubricated properly or undesirable things occurred. So casually in the pictures that wheel for the 550 Appears to be the sealed variety in the 470 appears to not be unless maybe it somehow been upgraded to be nice to get a picture