Last update May  12th. 2016

Case Opening-Closing Tools

December 12th. 2014


In watch repair, due to the variety of the watch case construction, there are many different tools used to open and close watch case.

The most commonly used watch case is type with the snap on case back. 

To open such a case it is required to use one or the other type of lever, or blade tool.

For closing the snap on case backs one can use either a dedicated press, as shown, or any of the glass fitting presses with a suitable set of Delrin dies that will not mar the case.
The screw back cases are usually opened using a special wrench designed for it. The adjustable hand held wrench is shown to the right.

However, it will unscrew only a limited number of case backs, typically ones with the rectangular and even number of notches.

To make the tool reliable and to remove play of the two tips it was necessary to slightly reduce thickness of the housing by lightly filing two halves, plus adding two new brass end pieces did the trick, as shown in the second image.

Jaxa wrench tool often used to open screw back watch cases with either even or odd number of notches.

It comes supplied with several sets of tips to fit many different case backs.

When using a hand held case opening tool it is advisable to hold watch in some kind of watch holder in order to make sure that tool will not slip and mar the case. 

For most water resistant cases, with a screw back, one must use a special press, equipped with various case holders and with tips made to fit different case backs.

Japanese made Meikosha MKS 220, heavy duty press, is shown on the image. 

This press can be used with many different heads made for various brands of watch cases. 

In practice it can open and close any size or make screw back watch case.

The MKS 220 set of five pairs of interchangeable tips intended to use with wide range of case backs. 
The MKS 220 case holder set, to fit case lugs' sizes from 11-12 mm, 14-15 mm, 16-17 mm and 18-20 mm.
Also, the MKS 220 heavy duty adjustable case holder designed for large watch cases, e.g. for diver's watches.

Case holder can open up, to hold watch case as large as 60 mm in diameter, shown fully opened on the second photo.

The set of accessories for the MKS 220 heavy duty adjustable case holder.


To strengthen the hold of a watch case there is a set of between the lugs holders, which fit large range of  case lug sizes: 

7-8/10-11 mm, 

12-13/14-15 mm and 16-17/18-20 mm.

The 32 mm diameter silicon rubber suction die shown fitted onto the press, ready  to open watch case without possibility of scratching it. 
The three dies, sizes 28 mm, 32 mm and 36 mm.
The new MKS product, the watch case holders, made out of hard plastic. 

Designed to accommodate larger watch cases like the ones used on watches for diving.

Meikosha MKS article No. 19600 fitting nicely and securely in the base of the MKS 220 press, as shown in the second image.

Silicon rubber 'wrenches' 49-60 mm in diameter  are very well suited for opening and closing most of the American made PW, whose cases are not of the snap-on style, but are made to screw the case parts together, either the back or bezel only, or both back and bezel.

Apparently these rubber 'wrenches' are big, and strong enough to be used as is, without having to make metal holding cup or any holder for that matter.

Tried and proven by opening few of the tough PW cases. 

Certain water resistant watch case designs use mono block case where movement can be removed from the case only from the top, after the watch crystal is removed.

For that purpose each manufacturer provides special tool like the one shown on the image..

Although a glass fitting and removing tool set, when the watch case is top loading it becomes case opening and closing tool.

Rudolf Flume "Ultra Ringe" tool set for fitting and removing of Ultra - D watch crystals.

Used for fitting and for removing unbreakable watch crystals in the size range of 200/10 - 325/10 mm with 5/10 mm step. 

The base of the tool case serves as the holder for crystals, which are placed in the recessed section of the corresponding size. 

When the ring is squizzed with pliers it will hold crystal leaving its bottom exposed enough for placing it securely in the bezel.

Rings are designed in a way that one cannot squash the crystal by excessively squizzing the pliers.  

American made pocket watches had their case parts, bezel and back cover,  typically screwed- on rather than snap-on as did most of European. 

To enable opening a PW case there was need for a special tool, a Vacuum Case Opener.

Some were made entirely of rubber, some had a wooden holder to allow the increase of friction.

Similar tool using the same principle is available for wrist watches.

This type works only with some cases, not with all.

It is inexpensive and it is still carried by most of the material houses.

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