MoT's WDF

Post by post, this thread seems to be morphing from the impossible challenge of how to open this watch's caseback to the more feasible challenge of how to destroy this #%%#& watch.

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The previous owner is in a psych ward somewhere, muttering something about case backs.

Maybe the caseback was glued in place by some sadistic person? Maybe red thread locker that requires high heat to loosen.

I too am invested in seeing this watch defeated and am quite enjoying the thread. More than that, I am learning new things and I appreciate that.

So I was able to get an inflation needle and blow up the caseback ball. I have to say this is my new favorite caseback tool. I have opened now three watches, including a Rolex that I thought I would need a special set to open. Its a fantastically simple and effective tool, and very versatile. That being said...it was not able to open this @#$%! watch. I looked a bit closer with the loupe at the seem where the caseback meets the case, and I see what looks like some green-blue corrosion in there. I also see a bit of thread on one side...making me think the caseback is perhaps cross-threaded.

At first I thought the ball was a dumb idea, but it has worked on every screw back watch I've tried it on.
Shame it met its match with that vintage piece.

Would a last resort be taking it to a watchmaker?
Let them figure it out?

I have successfully used a ball for years, on much younger watches.

It's a bummer you are still stymied.

What about temperature?

When you have a bolt stuck on a car, you heat it to break it free. Obviously you don't want to blow torch the thing, but some heat might help.

Alternatively, cold shrinks metal to the point where you can often freeze something like a wheel stud before hammering it in to make installing it much easier.

Wouldn't be the first thing I tried, but seems like your current situation is kind of...stuck.

Also, with a watch I had trouble getting the screw back off, my key was to build a jig to lock the watch down onto a board. I'm assuming you've probably got the watch stable if you've been able to break the caseback wrench, though.

I had an HMT that was cross threaded. My guess was that the wrong caseback was used. Oddly enough, when I installed an o-ring later, the case back threaded properly.

I think that I had to just get things clamped down very well and then using a caseback wrench I was able to get it to turn.

One thing I am pretty sure that I did was to apply downward pressure to the side that was higher. This allows a chance for the other side to lift up and come into proper alignment.

Your case is a different as the caseback is nearly fully down into the case, while mine had more of the threads sticking up to one side.

I don’t know if it will help, but have you tried jiggling the wrench back and forth to try to get a little play introduced. That is, wrench one way and then the next in fairly quick intervals? As soon as you hit a wall, switch directions? The play will probably be in the wrench itself, but I wonder if this could help here.

I am rooting for you Watchpalooza.

Edit: I think that purpose made case back due for this particular shape is probably your best bet here, though the cost may far exceed that of the watch if you went that way.

I think that I could 3D print one in ABS, which may be strong enough. Nylon would be better, but I can’t print in that material. If I made the part thick enough, then it should take quite a bit of force to deform. I could make a hole to be a size that a Phillips or Robertson screwdriver could easily pass.

This would have to wait until after I get back to work regular, so let me know if it is something I should start thinking about.

Riffing on one of Sporkboy's ideas, what about attaching a big hex nut onto the center of the case back using epoxy? With a good grip like that I expect you could apply a lot of torque using a reliable wrench.

Googling around, It sounds like there are methods (physical, chemical, thermal ...) for removing the epoxy after you get the back off, but idk. You could test different techniques on non-watch steel items, if you wanted to be sure. However, the case back etching would provide a textured surface difficult to duplicate in an experiment. Update to suggest filling the etching with wax (or something) before applying the epoxy so it doesn't seep into it.

I have also used a pipe wrench as a case holder when attacking a *very* stubborn case back (I finally won). I remember thinking that a bench vice was really the tool for the job.

BostonCharlie wrote:Riffing on one of Sporkboy's ideas, what about attaching a big hex nut onto the center of the case back using epoxy? With a good grip like that I expect you could apply a lot of torque using a reliable wrench.

Googling around, It sounds like there are methods (physical, chemical, thermal ...) for removing the epoxy after you get the back off, but idk. You could test different techniques on non-watch steel items, if you wanted to be sure. However, the case back etching would provide a textured surface difficult to duplicate in an experiment. Update to suggest filling the etching with wax (or something) before applying the epoxy so it doesn't seep into it.

I have also used a pipe wrench as a case holder when attacking a *very* stubborn case back (I finally won). I remember thinking that a bench vice was really the tool for the job.

The epoxied nut is a good idea. You would want to scratch up the nut a bit to give the epoxy more of something to grip. I would avoid filling the etching with wax since that will reduce the surface area that the epoxy can grip. This is assuming that you can use a solvent to later remove the epoxy from the etching.

Since my last comments were an edit, I want to flag that to Watchpalooza.

I didn’t have any measurements, the polygon cut out has the wrong number of sides and there are no curved cutouts. Still you should get the idea. Edit: Pleas note that the hole is meant for the insertion of a screwdriver.

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Yep, nothing left to do but...




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Had no opportunity during the week to do anything robust, but tried the ball and caseback wrench a few additional times with no success.

Alright, so the hardware store may be opening up again this weekend....if so I will try the following:

1) Liquid Wrench soak to loosen the seal. From this comparison, it seems to be the most effective penetrating oil:
2) Build a jig to hold the watch - have lacked the materials during lockdown
3) Start with case wrench, failing that epoxy a nut to the back and bring out the impact driver