Omega with plastic case back

[LiamB]

I have an omega with a plastic case back. I am fairly sure that it's not original and that ithe acrylic glass was added at some point and has cracked around the edges. Does anyone know how to remove this so the watch can be serviced? 

Thanks

[Gpsluvr]

They probably put it on with crystal cement and you will have to run a razor blade all around it until you get it to come off. Steve


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[rogart63]

That is a classic. Probably it was missing the caseback. And they put a acrylic crystal instead. 

[Watchtime]

just a cover to protect from dust,....original though...:)

[philipk5]

Try using a claw crystal lift tool first. If you are lucky it may not have been glued in. 

Good luck.

[marcoskaiser]

Hello Liam! Please let us know how did it work. I have a venus 170 missing the case back, and started to consider this option.

[vinn3]

  it may be epoxy.   if you can get the mvt. out of the case thru the front and deal with the case later.  if it is epoxy, use a jewelers saw and cut the crystal at the edge.   vin  

[philipk5]

2 hours ago, marcoskaiser said:

Hello Liam! Please let us know how did it work. I have a venus 170 missing the case back, and started to consider this option.

On the basis that the cost being minimal, and you do no damage by using glue, why not give it a go? I have successfully used acrylic crystals as case backs on several watches that would otherwise have been scrapped. 

Phil

[marcoskaiser]

1 hour ago, philipk5 said:

On the basis that the cost being minimal, and you do no damage by using glue, why not give it a go? I have successfully used acrylic crystals as case backs on several watches that would otherwise have been scrapped. 

Phil

That’s encouraging. I will do so. Thanks for the push!

[anilv]

Its a beautiful movement and perhaps the previous owner wanted it to be easily visible?

Anilv

[marcoskaiser]

I could not resist and started to make a case back to eventually fit a sapphire glass. I took an old orient case as raw material.

On the lathe, I gave up mesuring and only listened to the cutting to get hairs off the internal diameter of the stainless ring. Got a fit, but also a question: those of you who made the thing for real, what quality/hardness stainless steel should be used? And is there an optimal angle for the fittings of these click-on backs? 

Thanks!

marcos

Edited June 15, 2019 by marcoskaiser
Accuracy

[nickelsilver]

316L is the standard stainless for watch cases. Around 3-4 degrees for the angles, you don't want a sharp lip though, there will be a cylindrical land. Fitting is of course a bit of trial and error so a good fixture that allows removing and replacing on the lathe without introducing eccentricity is a must

[marcoskaiser]

4 minutes ago, nickelsilver said:

316L is the standard stainless for watch cases. Around 3-4 degrees for the angles, you don't want a sharp lip though, there will be a cylindrical land. Fitting is of course a bit of trial and error so a good fixture that allows removing and replacing on the lathe without introducing eccentricity is a must

Thanks nickelsilver! I turned a brass holder and left it on the chuck until the end. Only trouble was securing the steel. I used cianoacrylate, and washed it with acetone to release the piece. But heat would melt the glue. Must research some glue for this purpose. Any thoughts?

Best,

 

[nickelsilver]

I use cyanoacrylate very often, it's super handy. For something like this case I might use a friction chuck, usually plastic (pvc or delrin), that the case fits onto. Typically a short spigot that friction fits an inside diameter and a square shoulder to butt up against. Of course it only holds for light cuts with sharp tooling.

There are fairly sophisticated chucks that can be used but friction chucks are the traditional method, in the past they were generally wood.

[marcoskaiser]

4 hours ago, nickelsilver said:

I use cyanoacrylate very often, it's super handy. For something like this case I might use a friction chuck, usually plastic (pvc or delrin), that the case fits onto. Typically a short spigot that friction fits an inside diameter and a square shoulder to butt up against. Of course it only holds for light cuts with sharp tooling.

There are fairly sophisticated chucks that can be used but friction chucks are the traditional method, in the past they were generally wood.

Wood is surely more sustainable and cheap than brass...

I noticed that sometimes people like clickspring (makes videos on tooling and clockmaking) use some kind of superglue to hold metal together. 

At 6:54, if you get bored...