This is my brother Tim’s watch. The crystal had a deep gouge in the center and it was difficult to read the time. This was a mineral crystal and the gouge was so deep that polishing it out was not an option, hence the watch required a new crystal.
Casio with broken crystal.
I watched some YouTube videos to learn how to disassemble the watch and how to change the crystal. The watch comes apart differently than any watch I have previously worked on. You have to remove the bracelet to open the watch case.
Getting the bracelet off proved to be a challenge because there are screws on both sides of the bracelet and unbeknownst to me at the time, the screws were also glued with Loctite. Loctite is a glue that you put on the screw threads which makes screws harder, but not impossible, to remove. You can see the blue color on the bottom threads on the screws below.
Loctite Blue used on bottom threads of bracelet screws.
I found that steadying the watch, the bracelet, and two screwdrivers simultaneously was nearly impossible, especially given how tight the screws were thanks to the Loctite.
However, good news… this required a NEW TOOL (always fun to get new tools).
I probably could have done the job without the new tool but I rarely pass up the opportunity to buy a new tool. This little 3 pound chunk of metal holds a screw on one side of the bracelet while you unscrew the screw on the other side.
Bergeon 6730 Watch Bracelet Band Screw Holding Base Fitting & Removing Tool.
Once you remove the bracelet, the watch comes apart into these two pieces.
This red part that fits over the inner case is the “shock” part of G-shock. It is a shock absorber between the outer case and the inner case / movement.
Outer case and inner case.
G-shock ring.
The bracelet and the shock ring needed cleaning in the ultrasound.
Looking at the pictures you can see how much dirt accumulates over time, even inside the watch case.
Bracelet before ultrasonic cleaning.
G-shock ring before cleaning.
G-shock ring after cleaning.
Next we removed the case back and the movement cover. Removing the case back was a minor challenge because the case back was on so damn tight that it wasn’t budging. I have a special tool to remove the case back called a Jaxa tool. It has 3 adjustable prongs that fit in the divots of the caseback.
Luckily on the same day I was struggling with my (lack of) strength, my plumber, who is built like Arnold Schwarzenegger, came by to install a new sump pump. Even he could not get the caseback to budge until we put the watch in my woodcarving bench vise (his idea). Then it came loose. Major lesson learned here (use a vise).
Now we remove the movement and the movement ring. This is a white plastic outer ring that stabilizes the movement inside the case.
Case back.
Jaxa tool.
Movement protector.
Movement inside the case.
Watch movement with movement case.
Movement ring.
To push out the crystal you have to put pressure on the center area inside the silver area (see above picture). And, you guessed, it I needed another NEW TOOL! Yay. I love my tools.
Actually these are just a new set of dies that fit my existing case press.
Of course, even the smallest die didn’t fit inside the silver area (poor planning on my part). So I resorted to a smaller circular die. I had mixed results as you will see below, but it got the job done.
New die set for removing crystal.
Having “removed” the old crystal, all that was left to do, was to press in the new one.
That job was not without trepidation because I have shattered a few crystals during installation. Most acrylic crystals are around $3.00 so no biggie if you ruin one. I usually buy a few extra crystals.
However, mineral crystals are more expensive. This crystal was $30.00 and I only found one, in England, so shattering it would have been a bad option. For this I was able to use one of the dies from my new die set above.
At least I didn't damage the outer metal part...
It looks worse from the front.
While acrylic crystals usually crack, mineral crystals shatter.
After that scary moment, reassembly was straightforward. I did a light polish on the bracelet and the case.
I created a Casio account online and was able to use bluetooth to sync the watch with my iPhone to set the date and time.
The watch looks much better now that you can read the time through the new crystal.
Bright, clear new crystal.