Bergeon and Japanese "MKS" Snap-On Case Opener

Bergeon Opener (black, on the right)
Another tool I should have bought years ago. The prize of ca. USD 20 (2006) for this very simple tool seemed high. But this is today my favorite tool to open snap-on cases as they are often found on quartz watches. The tip of the tool is a lot thinner then the one found on the case opener knife. In fact I suspect those knives have been developed at a time mostly pocket watches have been used. I have really rarely found a watch with a snap-on case back where I could use the opener knife. I find the opener blade far too thick and the handle of the knife too thin. Most of the times I used it, I slipped, cursed and then thought of another solution. Today the solution is this really great Bergeon opener. The tips must be great quality hardened steel. I have opened many watches and the big handle allows to apply quite some torque. Still, there is no sign of wear at the tip at all! Below is a picture on how to use the Bergeon opener best (this is my personal experience and everyone will develop his or her preferences, so always think of my advice as a guideline along which you could develop your preferred method rather then the ultimate truth):


I use a multiple fold paper to support the heel of the opener on the lug. Multiple fold is important since there will be quite some force if the case back sits tight. Also scotch-tape or painter's tape is too soft and will not protect the case or lug from an imprint of the heel of this tool
Actually this watch as a groove in the case back at the 9 o'clock position where the opener should be positioned. The picture above shows the general position where most watch cases offer a little groove to facilitate opening.

The brown "MKS" opener is Made in Japan
And does a good job for smaller (e.g. Ladies') case backs or case backs that do not have a groove near on of the lugs. The tip is sharp, be careful not to drive it into your palm! Also you can file the tip down to a flatter shape and then make sure you take the sharpness of its edge with a water stone. You want it flat, but you do not want a "dagger". Experiment with the two contradicting requirements: as flat as possible vs. being able to apply a good opening momentum.

Some hints on how to open Snap-On Case Backs

Most Watches with snap-on Backs
have a groove (sometimes really hard to see find without a loupe) near the lugs away from the crown. The case back is normally filed off a tiny bit offering an opening for the case opener to grip and pry the case back. Some Quartz case backs have either a groove or a extension of the case back normally at 6 o'clock. Some watches do not have any additional groove between case back and case. And that makes them harder to open if the case back sits tight.

 In any case, please make sure you thoroughly check the entire circumference of the case back for an opening help, groove, etc! It might save you a lot of troubles and prevent opening marks! Although it has to be said, that despite "opening helpers" (grooves etc.) snap-on cases can be very tough to open. It is really a matter of experience, patience and the right tool.

My LAST RESORT opener - the HOROTEC Case Crap
I am the happy owner of a HOROTEC Case Crab, for the "impossible" case backs. Placing the watch correctly on the Case Crab takes some time, but that will hopefully avoid opening marks. However - and this should not discourage you from trying - there will be always watches that seem impossible to open! The HOROTEC Case Crab has already paid for itself by saving me numerous trips to the watch repair shop.

"The impossible to open case backs" and a little anecdote
There are many reasons: poor case back design, too soft case material (chrome plated brass as often found on Russian watches), problems with tolerances: some case backs simply sit too tight. This is not a complete list of reasons why some watches are so hard to open. I have often put the watches to be opened aside for a day or two and contemplated alternative tools for opening. Professional watchmakers often do not have that luxury and customers often have no idea what it takes to open some case backs without leaving marks. They just want the battery replaced as fast as possible. If everything fails, then I take the watch to my watch parts shop. They have a staff there, that is an absolute magician with her Chinese folder knife. I had once tried to open a Michel Jordi watch of my wife and I had tried all my tools. Really all of them! In vain! The case back started to deform itself and the case was already showing many marks from unsuccessful opening attempts. Finally my pride allowed me to pocket the watch and drive to the parts shop. The girl that was in charge of "impossible case backs" turned around for a very short time. I saw that she bent over the watch and within seconds, she turned around smiling with the open watch in her palms. Magic, no, experience! She had opened a Chinese folder knife with a thin but not sharp blade. And of course I asked her what allowed her to open this impossible case back. Her trick was a quick scooping motion: she simultaneously pressed the blade towards the case back while turning it quickly. A word of warning: this takes experience. I have noted that sometimes  a bit of speed really helps. But on the other hand, a bit of speed when opening also increases the risk of leaving really ugly opening marks or even worse, drive the blade right over the circuit of the Quartz movement if you are not able to stop the inward motion quickly. The best advice if a case back does not open is to see a trusted watch repair professional. Not just the next best watch booth in the shopping mall, unless you know the person there is really skilled and has experience.

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