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Posted

My dad taught me to install crystals using an Electro-Vise.  That is all I ever recall using.  Since my renewed interest, I have used this other device (shown in the picture).

I have, among my tools, a BB Crystal press, but frankly, I have never tried to use it for installing crystals.  Pressing down on a crystal that is (by design) 40+ microns larger in diameter than the case just scares me.

I like the concept of the Electro-Vise and the other (unknamed) device because you are causing the crystal to compress uniformly around the circumference and thus reducing the diameter to the point where the crystal gently slips into the case.

For a plain old round domed crystal that I can buy for a buck...I guess I don't worry about a screw up.  But if I buy a special crystal from NOS with, say, a date magnifier--maybe the last one in known existence--I want the best approach I can use.

So, I appeal to the experts to share their methods!!  Thank you in advance.

Posted

Without seeing the crystal and case you're talking about I don't think sure advice can be given. I'm not familiar with any of the brands you have mentioned.

For a general discussion check topic below

 

 

Posted
38 minutes ago, LittleWatchShop said:

My dad taught me to install crystals using an Electro-Vise.  That is all I ever recall using.  Since my renewed interest, I have used this other device (shown in the picture).

I have, among my tools, a BB Crystal press, but frankly, I have never tried to use it for installing crystals.  Pressing down on a crystal that is (by design) 40+ microns larger in diameter than the case just scares me.

I like the concept of the Electro-Vise and the other (unknamed) device because you are causing the crystal to compress uniformly around the circumference and thus reducing the diameter to the point where the crystal gently slips into the case.

For a plain old round domed crystal that I can buy for a buck...I guess I don't worry about a screw up.  But if I buy a special crystal from NOS with, say, a date magnifier--maybe the last one in known existence--I want the best approach I can use.

So, I appeal to the experts to share their methods!!  Thank you in advance.

Sorry, I meant to post this picture

2021-02-01 08_52_06-Photos.png

2021-02-01 08_54_23-BB Style Watch Crystal_Case Press with Dies — Mozilla Firefox.png

Posted
30 minutes ago, jdm said:

Without seeing the crystal and case you're talking about I don't think sure advice can be given. I'm not familiar with any of the brands you have mentioned.

For a general discussion check topic below

 

 

I am reading it now.  Here is one interesting post from that thread:

Interesting

Posted

The BB Crystal Company set that you have got on the left is for installing armoured or tension ring crystals. These have a metal ring on the inside of the crystal to keep the sides of the crystal rigid, so using a crystal lift like the Electro-Vise or the Bregeon would be very difficult. The sides of the crystal, and the sides of the rebate into which the crystal fits are parallel, and the crystal is fractionally larger than the rebate, such that when it is installed it is a tight interference fit. The flat dies go on the bottom to support the case, and the inside rim on the upper dies are bevelled, and you select a die that fits over the crystal such that the bevel is in contact with the edge of the crystal dome. The shape of the bevel coupled with the amount of force that the press applies is sufficient to bow the very bottom of the crystal inwards to get it into the top of the rebate, then push it all the way home. The rigidity afforded to the crystal side courtesey of the tension ring allows the crystal to make a very tight, water reisitant seal against the sides of the rebate.

The crystal lift is ok for installing standard acrylics but in my opinion it's not the best method. I use one of these..

20210201_182842.thumb.jpg.8251bc664f5bcb4876e70e570802ca37.jpg

You have a felt covered lower die that is significantly smaller than the crystal, and a concave upper die that is only slightly smaller than the crystal.

20210201_182909.thumb.jpg.af51ebbfe913f9be0e73a957a0a14679.jpg

The case or bezel is placed over the lower die, the crystal sits on top of the lower die.

20210201_182946.thumb.jpg.ce625e88adbbf87b683288d96a0cf5fd.jpg

The upper die is then brought down on top of the crystal and pressure applied causing the lower die to push the middle of the crystal up into the upper die, making it more domed which at the same time reduces the diameter of the crystal skirt.

20210201_183024.thumb.jpg.009700d265d4e04ca868ebb663c9ae75.jpg

The bezel or the case is then brought up so that the crystal skirt sits inside the rebate, and the upper die is raised, releasing the pressure, and the crystal resumes its proper shape with a flatter dome and wider skirt which grips into the rebate.

The sides of a standard acrylic are actually slightly conical, not parallel, and the rebate has a similar conical section, such that as the crystal sides expand in the rebate the sides of the crystal also force the crystal down onto the seat. This creates a contact seal against both the sides and the seat of the rebate and stops the crystal falling out.

20210201_191327.thumb.jpg.44dfe68a6d84e9fa6e549a086fe65b4e.jpg

The set of dies on the right in your pic is for installing glass crystals which are usually pressed into an "I" or "L" shaped gasket.

  • Thanks 4
Posted

Marc.  Brilliant.  This machine of yours comports with the way I imagined it should work.

What I am going to do is modify my BB press to use this concept.  All I have to do is design and 3D print the die.

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