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In separate purchases I have probably 300 glass crystals. I find that numbers on them will not always be the same size by another maker.
The crystal size I needed once was a 20 5/16.
Man that puppy must be scarce because I found one in the whole lot, but broke it trying to snap it in.
I researched the whole group and Yes I had broken the only one. So, I used a 20 6/16 but found a few of different thicknesses. This is a full hunter PW.
I got a thin one almost there before it broke. So I went to filing on the thicker one.
The super smooth stone like file is probably the jeweler diamond file. I just rotated while filing in various movements, circular, side to side, at an angle. I did not use a paste or water, I got it to work. Snapping in on several segments around the bezel.
Since I did not used anything but a no doubt impregnated file of other substances, I didn’t actually know how it would progress. I knew I was removing glass. But,,,,,, I was seeing little edge ‘spiders’ and tiny chips along the circumference.
Got it in OK, but are these edge defects preventable? ThankYou, regards.
James , I too have 300 crystals and not the right one ! William White is our resident crystal man , he is actually making new crystals , search his posts . I do some stained glass work and almost every piece is ground to fit and remove burrs , I use a "wet" diamond burr , the wet is to keep silica from killing you , it's just a sponge touching the wheel . So grind away ! I also have this little gadget , but have not put it into use , I was thinking of using a stone on a hinge for the grinder
James , I did not quite answer your question , In my opinion it is ok to file or grind a crystal , try using a sharpening stone , keep your angles correct , make sure the case is clean of old glue and dirt , I try to get a couple crystals and see which one fits best , rotate them when fitting - not all are round same with bezels.
As Kevin mentioned above William White manufactures new crystals.
You may find this topic of interest...
How Watch Crystals Are Made
|IHC Life Member
William White here. You can successfully reduce the diameter of a glass crystal using #400 silicon carbide (wet-n-dry) sand paper taped to a wood block. What you'll need to do though is spin the crystal somehow. A device like Kevin's would be ideal. Here's a link to a short video showing the setup I use for holding crystals during beveling and finishing operations:
What's important to remember is that silicon carbide breaks down quickly when used with glass so keep it moving and continually introduce fresh grit to the work. Keep the surface of the paper damp but don't use too much water; if the paper appears wet then it's too much and the work will be over-lubricated. Once you achieve the diameter you want, simply polish with a worn area of the paper. This will work quickly and leaves a well healed, chip free edge. You can also just do this by hand but it's going to take a lot longer.
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