Removing a screw-type watch case back

Removing Screw-type Case Backs
I have been repairing Seiko Kinetic watches for over 12 years.
I estimate I have also replaced over 200 Capacitors in Seiko Kinetics.
One of the biggest frustrations by far when I work with a Seiko Kinetic is removing the case back.

The Seiko Kinetics started out as the AGS (Automatic Generating System) in the 1980s.
The "Kinetic" began in the 1990s.
They were wildly popular.
(Seiko told a big fib when they advertised "Never needs a battery", but that story is for another time.

Because the Kinetics I work on were made as far back as 1991 they are now as much as 28 years old.

For this reason alone the backs can be atrociously hard to remove.

I did have success with many screw-type case backs by Super Gluing a lug nut on top of the case back, letting the glue set thoroughly (I used baking soda as an accelerant) and then merely turning the lug nut with a wrench.
Then, once the case back came off, I simply soaked the case back with the lug nut attached in a small amount of Acetone, which dissolves the Super Glue, and the case back is separated from the lug nut.

BUT: As you know many Seiko Kinetics have the clear see-through window.
The lug nut method does NOT work on those types of Seiko Kinetics.
The see-through window turns, instead of the case back, and separates from the case back.

For tools to remove a screw back I went through many types over the first few years, with aggravation and foul language.
I quit watch making forever at least once every 2 weeks.

1) I tried the standard 2-pin case back opener. (See photo)

The problem with the venerable 2-pin opener is that it does not give you much of a fulcrum arm.
I remembered from studying Physics that torque is dependent on the arm of a fulcrum.
The longer the arm, the more torque applied.

And no matter how hard I turned, many many case backs did not budge.

And I had a lot of injuries to my hand, especially at the base of my thumb.

2) I also briefly tried the classic 3-pin case back opener. (See photo)
This opener does have a longer arm, for greater torque.
But for me this opener was almost impossible to use.
I had great difficulty lining up the 3 pins, and spent a lot of time doing so, and then when I moved the arm in a circular fashion to turn the case back a pin would slip out and I would have to start all over again.

A major drawback of the 3-pin tool is it blocks all your view of the pins and holes.

The 3-pin opener I began to truly despise.

The 2-pin doesn't work often but at least it doesn't take 10 minutes every time it doesn't work.

3) I scoured eBay and Amazon and Chinese web sites for other case back removal tools.
I did have a hearty laugh when places advertised rubber balls that they claim you press against the case back and simply turn and magically the case back moves and opens.
Don't be a sucker and buy any of these. A total lie and a complete waste of money.

So then I realized the problem mostly was in the fact that when turning any tool I was applying pressure on only one end of the tool, which made keeping all the pins in their holes nearly impossible.
One pin was being pressed down while the pin on the other end was being tilted up, and would slip out.

So I knew I needed to combine something with a longer arm, that was simple to place the pins into the screw back case holes, did not block the view of the pins/holes.
Nothing was available commercially.

So I made my own, in a really amateur way. (See photo)

I taped a 2-pin opener to a heavy file that I bought.
The file is long enough to provide a substantial arm for the fulcrum, but no so large that it takes a
wide arc and is difficult to wield.

The difference of course is not I can place my watches in a watch holder, place the watch holder in a hobby vise, place the simple 2-pin opener into 2 pins of the watch case back, press down with BOTH hands on BOTH ends of the file, which causes BOTH pins to be firmly seated in BOTH case back holes, and what an immediate difference.
Astonishing difference.

For the first time ever pressure was being applied equally to both pins, with a long arm causing a great deal of torque, and reluctant case back after case back after case back came off, with relative ease.

A couple of things I learned to do very early on that helps a lot is
1) Spray around the entire circumference of the case back with Contact Cleaner
I use WD40 Contact Cleaner (see photo) available from Amazon
2) Gently and slowly and ultra-carefully work around the entire circumference with a box cutter
I spray Contact Cleaner directly onto the box cutter blade, and then work only 1/8 inch at a time.
3) By only sawing back and forth 1/8 inch at a time with the box cutter I am much less likely cut myself. I am in no hurry, because bleeding all over the carpet would take time to clean up.
And I don't know about your own local ER, but my local ER is very expensive.

I still pre-treat with WD40 Contact Cleaner, as I do think it melts through some accumulated crud, on watches that have been worn for 20 years or more.

I am hoping some of you have better ways you will tell me about how to attach the 2-pin tool to the file.
I will probably use electrical tape, pulled very tautly, the next time I have 15 minutes.

I thought also about first Super Gluing the 2-pin tool to the file, and then also taping it.
Just to see if that helped in any way.

And I suppose there is a way to weld the 2-pin onto the file.
But I know nothing about welding.
Nothing.

Anyway, send me your suggestions.

I hope this helps you remove a stubborn screw-back case back.