Case Openers: Overview

Opening watch cases is not the easiest of the watch making tasks for us that don't do this on a daily basis. But it is always the first to be done. I admit that I have been very scared at first when opening watches, especially watches that were not mine. No one likes opening marks or scratches on case backs.
And when browsing the fleamarkets here in Bangkok, I have seen some seriously damaged case backs. I suspect that the sellers tried to open the watches without having the proper tools and if they could not open the case backs, the watches end up on the market at a temptingly low price.

My personal experience told me that to safely open watches without leaving marks means that

• you have some practice

• you have the right tools

• you have to be able to abort the opening attempt and bring the watch to a watchmaker or a watch parts shop

Case back is closed too tight...
I had some good success opening vintage watches by applying fine oil around the rim of the case back and wait for 24 to 48 hours. The oil will work on rust or goo that has built up over the years. I normally try different openers first and when I feel that too much force is required, I will use the "soaking method". It is really worth waiting a day or two instead of ruining a case back or slip and leave ugly opening marks.

Last but not least: It is a myth...
That a case back has to be closed with a huge momentum in order to guarantee water resistance. Many people use too much force when closing case backs. A gasket ring in good condition is much more important then too much closing torque

A) Hand held case back openers

Types of Case Backs	Bergeon 5394 Movement Pad	JAXA Universal Case Opener Swiss Made (If you are more experienced, go for the single handle version)	The very "Poor Man's" Alternative: China Made Openers	Meikosha 19400 Made in Japan	Bergeon 5338-1 F Swiss Made**	Bergeon 5537 Swiss Made
Typical Asian street price (ca. 2003, since then we had an oil price almost doubled, so expect higher prices today)	USD 10	USD 100	USD 11 - 14	USD 50	USD 70	USD 80
For >>>	N/A	Cases with Slots Cases with round Holes	Cases with Slots Polygonal Cases*	Cases with Slots Polygonal Cases*	Cases with Slots* Polygonal Cases	Cases with Grooves (Rolex)

* grey choices in the  For >>>  row mean, that the case opener can open those cases, but is not the ideal tool.
** additional bits for the Bergeon 5338 are available: for Cases with Holes, Curved Edges and Cases with Grooves, although I would always prefer the Bergeon 5537 for Cases with Grooves

B) The professional Bergeon 5700Z and accessories

Bergeon 5700Z and Accessories	Explaining the Vice	Lug jaws	How to use it	Using Rolex openers 5537	5537 Mounted
Works with almost all case backs depending on the accessories and bits. You should see this Bergeon opener or a very similar opener in every professional watch repair shop. Once you have one yourself, you could not imagine how you opened watches before. The machine costs ca. USD 350 but reduces the risk of the watches being scratched while opened a lot.

C) Pocket case opener tools for case backs with slots (screwed case backs) and snap-on case backs:

D) Case opener tool for non-screw (snap-on) case backs:

Opening grooves
Please note that many watch cases or case backs provide opening grooves to facilitate positioning the opening tool. Sometimes the cut-outs in either the case backs or the watch case are very small and you probably find them with a loupe only or by driving your finger nail carefully around the edge of the case back. Common positions for grooves are

• Most often at the 5 o'clock position opposite the lower right lug (you are looking at the watch from the front with 12 o'clock pointing up)

• Alternatively the opening grooves are located opposite the other lugs at 7 o'clock, 11 o'clock or 1 o'clock

• Sometimes the grooves are right in between the lugs either at 12 o'clock or at 6 o'clock

• On some Seikos I have found grooves in the case back opposite the crown at 9 o'clock (e.g. the Seiko Quartz Discovery series).

It is really worth to look for these opening grooves as they allow a much saver positioning of the manual opening tool. The Case Crab opener below is especially helpful for very tight case backs or where an opening groove is missing. Please find additional Opening Hints here.

HOROTEC MSA 07.115 Case Crab	Bergeon Tool - my Favorite!	Japan Made Meikosha "MKS" and Bergeon Opener (Opening Hints)	A modified mini Victorinox Knife
Snap-on Cases normally found on Quartz watches (There are some exceptions, notably some automatic Omegas come with snap-on case backs)

E) Case opener for screwed case backs without groves

I have always considered this kind of case back the toughest to open. Especially if the watch is quite old or if the case back sits very tight. In September 2011, I witnessed an employee in my favorite watch parts shop using a Cricket Practice Ball. And what a revelation this was! I went straight home and tried that Cricket Practice Ball on one of my Pocketwatches with no grooves on the case back. I was able to open the case back with ease! What might have helped is the fact that my Cricket Practice Ball is a couple of years old and has become a bit stickier then it left the factory. It is simply perfect to open screwed case backs without grooves!

A Cricket Practice Ball

Screwed Case Backs without Grooves (these are normally the toughest to open for us non-professionals)