Stubborn case back screws - any tips?

[Zendoc]

Hi All,

I’m trying to remove the case back of an Eberhard & Co watch.  It’s held in place with 8 stainless steel slotted screws which are just impossible to turn. They were removed when the watch was professionally serviced a couple of years ago, but they’re not budging now.  I’m afraid of applying too much torque in case the head twists off, leaving me with an even bigger problem.

Any suggestions for how to loosen these case screws?  I’ve seen references to the application of heat with a soldering iron, but I suspect that might be a last resort. Penetrating oil is also mentioned elsewhere as a remedy for stuck screws, but if I use that, I suspect I’m risking getting it into the movement. 

Any advice, gratefully received.

Cheers,

John 

[jdm]

8 minutes ago, Zendoc said:

. It’s held in place with 8 stainless steel slotted screws which are just impossible to turn.

Just for reference, could you post a clear picture please. That is needed with almost any question.

However, is these are tight, normally what is used is a perfectly sized and dressed driver, with a torque knob on the handle. It is possibile that tread lock has been applied, in that case just apply a bit of heat with a soldering iron. That is done when a shop tries to have the watch given to them only for work.

[Zendoc]

Thanks for the reply jdm.  I’ve attached a pic.  I hadn’t thought about the thread lock. Or the reason they might apply it.  Some of the screws have slightly damaged slots and I have a replacement set I’d like to drop in, just for cosmetic effect.  I had the back off prior to sending it for service and I recall that the screws were easy to take out.  

I’ll apply a bit of heat tomorrow and see what happens.

 

[Kalanag]

As JDM says, dress your screw driver to fit as perfect as any possible into the screw heads.

[Zendoc]

Thanks Kalanag - I’ve done that and can apply plenty of torque - so much that I’m worried about twisting off the screw head. But the screws just won’t move - yikes!

I don’t know what they’ve done to wedge them in so hard - but JDM wondered about thread lock and I’ll explore the heat solution tomorrow when I crank up the soldering iron. 

[Paul80]

If you can't shift them with a good fitting driver I doubt it's thread lock, sounds more like they used super glue instead of thread lock, by accident because someone picked up the wrong bottle or by design because you pee'd someone off, heat or a drop of acitone on the screw heads should soften it enough

[Zendoc]

Well, just to complete the loop - here’s what moved those screws in the end.  

A bit of heat and a bit more torque moved 7 of them.  The 8th was very difficult.  I tried heat, followed by cold, lots of torque applied bravely, but to no avail.  In the end I used DeOxit applied with an oiler to the margins of the screw head.  I presume capillary action drew it under and into the thread.  I left it a couple of hours and then tried again - this time with success.  Now all 8 are removed.  I was sweating on the last one, because the slot was already damaged from where people had been in before and I knew I had a high chance of wrecking it. The heads are surprisingly soft. 

Anyway, mission accomplished.  Thanks for everyone’s input.

 

[Paul80]

Glad you got there in the end, was there any residue in the threads to give a clue as to what they used to lock them in, coloured it would be thread lock clear it could be glue, nothing they used a gorilla to tighten them

[clockboy]

As already suggested only use a very good fitting screwdriver.. If still no joy then try a little heat to one of the screws and test again.. This will test if the screws have indeed been fitted with loctite. If glued then you have a massive problem. If it was me I would then just return the watch and be honest with customer and suggest returning it to the original repairer. The danger you have in your quest to open the watch and you shear a screw head your liable..If it is your watch then of cause that’s a different matter.

Edited July 10, 2022 by clockboy

[Zendoc]

It was my own watch, Clockboy, but it didn’t lessen my concern - shearing the head off would’ve been a major issue for me    Anyway, it worked out OK.  Maybe the Deoxit helped, maybe it was a placebo.  Not sure.  There was no residue on the threads to suggest they’d been thread locked.  I’ve replaced all 8 screws with a set of Eberhard originals and they go in  and can be removed very smoothly now and the heads are pristine and I intend to keep them that way.  Some of the originals were ratty, having been damaged by someone using drivers too small for the slots. 

 

[clockboy]

5 hours ago, Zendoc said:

It was my own watch, Clockboy, but it didn’t lessen my concern - shearing the head off would’ve been a major issue for me    Anyway, it worked out OK.  Maybe the Deoxit helped, maybe it was a placebo.  Not sure.  There was no residue on the threads to suggest they’d been thread locked.  I’ve replaced all 8 screws with a set of Eberhard originals and they go in  and can be removed very smoothly now and the heads are pristine and I intend to keep them that way.  Some of the originals were ratty, having been damaged by someone using drivers too small for the slots.