The Amateur Watchmakers Corner ... Volume II

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You are on Volume II of the Amatuer Watchmaker Corner..

Volume I can be found here: Volume I

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#2 - Installing a Clear Caseback... Part I
#3 - Installing a Clear Caseback... Part II

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Once you have decided to install a clear or transparent case-back on your Rolex, you have to find a good one.. There are a few makers of these interesting accessories, and for this experiment I have chosen one manufactured by well known German Master Watchmaker, Thomas Preik... http://www.thomas-preik-shop.de/

I have decided that this installation will take two installments. The actual change is a minute or two, but I will drag it out to give the purists something to agitate about, and I will use the rest of the time to investigate what we are doing.

Here is the actual Sapphire glass, Stainless Steel case-back we are going to use:


Before you put anything on your watch, you should know exactly what it is and exactly what you are doing. So, let's take a closer look at this product:
The diameter of the case back is 1.400"/35.55mm, but we need more.

Micing the thickness of the Sapphire, we see that it is .035"/.90mm. Pretty respectable as the Stainless Steel case-back we are replacing is less than that at .031"/.80mm.


Diameter of the glass is 1.100"/28mm, almost the same size as the dial crystal at 1.200"/30mm:


Looking at the backside and the threads, we see machine cut threads. A small amount of tearing, but that is to be expected with Stainless... a difficult metal to get a uniform smooth cut:


Back at the face, the sapphire disc has been press fit into a machined ledge with what appears to be a composite gasket...very similar to pressing on the crystal, except to an inside ledge, rather than on an outside one:


Looking at the backside, we can readily make out the ledge the disc is pressed against.


In the next part, we will round up some tools and undertake the task... and make a comparison or two...

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If you have been following this, you know we have been exploring a clear case-back for our Rolex.

This is the case-back that we will be installing; a very nice product made by German watchmaker Thomas Preik.


Now that we know what we are going to be putting on the back or our Rolex, we need to round up some tools. These should do:


The first task is to actually remove the case-back on the watch. To do this we need a good opener and a 29.5mm Rolex case socket. Here you can see the set-up that will hold the watch securely and safely, and also break the seal and unscrew the back enough to be finger loose:


Once removed, you can see the O-ring that is the primary back seal. We will remove this one, clean the area with a wood dowel and gauze, apply a light coat of silicon grease on a new O-ring, and reinstall it ready to accept our new case-back.


Now that we have our original back off, let's take a look at the two of them. You can see that the original is a bit thinner. It also tapers to a flatter edge. It is, of course, necessary to keep the thicker area larger on the new one to be able to hold the clear sapphire disc:


Laying a straightedge across the tops, it is now more evident that the new sapphire case-back is slightly taller.... we will see if that is evident in the final install:


You can see here that the case-backs install differently. The original uses the Rolex socket, and the clear back needs a spanner:


In order to install this properly and without mishap, I will use this three pin model that is fully adjustable and will fit the case-back tool holes properly and snugly:


The advantage of this type of case opener is that the spanner can be centered under the screw and held in place squarely. This way proper torque can be applied, and there is almost zero risk of slipping off and scratching our watch:


After snugging the back down, then placing it in the opener for final torque (45 inch pounds), and ensuring that the gasket has remained in it's proper position and is not exposed..... we are complete:



We can now put the bracelet back on and take another look at that beautiful Rolex movement as it comes to life in front of us. As mentioned, the sapphire case-back is slightly taller than the original. Before installation the thickness of the watch was .485"/12.32mm, after installation, the final thickness is .494"/12.55mm, a difference of .009"/.23mm. This is almost insignificant when it is on the wrist and it feels the same without any clasp adjustment.


With everything put back together and wiped down, it's almost a shame to put it on our wrist and cover it up.


This case-back is well made and construction detail is excellent.

The final step is to wear, or take it down to our local watchmaker and ensure that it is as water proof as the original......... I'll let you know if it fails.......but I'll bet it does not.

This is really a pretty simple project and can be done in the amount of time it took to read about it. It can also be personally rewarding as we journey along our horology hobby path........

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