GandalfPC
11-02-2002, 01:25 PM
Hope this will come in handy for those of you frustrated with all those crystals you have that are always too small or too large, never the right size for a snap fit...
I have a small selection of crystals for 12, 16, and 18 size watches - certainly not the titanic collection that is required to find a snap fit crystal when I need one. If I am lucky I can find one the right size to glue in, but often even that is impossible. Most of the time they are way too small, or too large to fit into the bezel. Then yesterday I decided to take a chance and found a great solution - now I have three watches with beautiful snap fit crystals in place, and can fearlessly purchase crystal lots off of ebay without worrying about being stuck with a pile of glass that won't fit...
Step 1: Find the closest fitting crystal you can that is a little too large to fit (although they can actually be several sizes too large - it just takes a bit longer).
Step 2: Take some emery paper (I used 250 and 600 grit - the courser paper cuts very fast and the finer allows for small adjustments near the end of the process), lay it on a flat surface, and don some protective glasses and a proper dust mask.
Step 3: Hold the crystal between your thumb and first two fingers so it is straight up and down, with it's edge resting on the sandpaper - your fingers should be pointing downward, and your wrist and arm should be at a right angle to your hand (I will post pictures below to make this clear)
Step 4: Rotate your wrist while keeping the crystal in contact with the sandpaper - it will draw a fine white line on the paper. I start each stroke with my fingers pointing to the 7 o'clock position and finish each with my fingers pointing to the 5 o'clock, making a line on the paper 6 to 8 inches long. Each stroke on the paper is made left to right. I lift the glass from the paper, and while rotating my hand back to the 7 o'clock position I rotate the glass slightly with my fingers (somewhat less than a quarter turn) so that after several strokes I have gone all the way around the crystal.
The trick is to keep the crystal circular by always making sure you are twisting your wrist, not moving your arm - this grinds down the edge and keeps it circular (if you moved your arm instead it would make a flat spot.)
If you use too much pressure you will chip the edge of the crystal, or break the crystal - you only need enough pressure to leave a white line on the paper - a bit of practice will teach you how much pressure you can get away with, but it is better to err on the side of too little (which just means the process will take longer) than using too much (which means a broken crystal and perhaps a cut finger).
I don't want to hear any stories of people getting cut out there, so feel free to wear thin leather gloves (I broke a few crystals while experimenting, and always do it without gloves - no cuts yet :smile:) The thinner the crystal the more gentle you should be (which should go without saying). At this point (I have done about a half a dozen) I am sure to not grip the crystal too tightly or press too hard.
After every 10 strokes or so be sure to test fit the crystal into the bezel and make note of your progress. DO NOT apply more than VERY gentle pressure if it looks like it will go into place - when it is very close to finished it will look like you could give it a push and get it into the bezel, but you will only break the glass and have to start over with a new one. When you get to this point you want to switch to a finer sandpaper and test fit after every few strokes.
There is a bit of art involved - rotating the glass in the bezel (since most bezels are not exactly round, and the glass may not be either) to examine how it is going to fit, perhaps grinding down one side of the crystal a bit more - once again, a bit of practice will tell you what you need to know.
Most important is patience as you near the correct fit - try pushing it into place too hard and you will snap it, grind it too much and you will make it too small and need to glue it in (not the worst thing in the world, but much more satisfying to snap fit it without glue!)
This whole process will only take 5 to 15 minutes if done correctly (even with a crystal several sizes too large).
http://jasongoldman.com/pics/b.jpg
http://jasongoldman.com/pics/c.jpg
http://jasongoldman.com/pics/e.jpg
[This message has been edited by GandalfPC (edited 11-02-2002).]
I have a small selection of crystals for 12, 16, and 18 size watches - certainly not the titanic collection that is required to find a snap fit crystal when I need one. If I am lucky I can find one the right size to glue in, but often even that is impossible. Most of the time they are way too small, or too large to fit into the bezel. Then yesterday I decided to take a chance and found a great solution - now I have three watches with beautiful snap fit crystals in place, and can fearlessly purchase crystal lots off of ebay without worrying about being stuck with a pile of glass that won't fit...
Step 1: Find the closest fitting crystal you can that is a little too large to fit (although they can actually be several sizes too large - it just takes a bit longer).
Step 2: Take some emery paper (I used 250 and 600 grit - the courser paper cuts very fast and the finer allows for small adjustments near the end of the process), lay it on a flat surface, and don some protective glasses and a proper dust mask.
Step 3: Hold the crystal between your thumb and first two fingers so it is straight up and down, with it's edge resting on the sandpaper - your fingers should be pointing downward, and your wrist and arm should be at a right angle to your hand (I will post pictures below to make this clear)
Step 4: Rotate your wrist while keeping the crystal in contact with the sandpaper - it will draw a fine white line on the paper. I start each stroke with my fingers pointing to the 7 o'clock position and finish each with my fingers pointing to the 5 o'clock, making a line on the paper 6 to 8 inches long. Each stroke on the paper is made left to right. I lift the glass from the paper, and while rotating my hand back to the 7 o'clock position I rotate the glass slightly with my fingers (somewhat less than a quarter turn) so that after several strokes I have gone all the way around the crystal.
The trick is to keep the crystal circular by always making sure you are twisting your wrist, not moving your arm - this grinds down the edge and keeps it circular (if you moved your arm instead it would make a flat spot.)
If you use too much pressure you will chip the edge of the crystal, or break the crystal - you only need enough pressure to leave a white line on the paper - a bit of practice will teach you how much pressure you can get away with, but it is better to err on the side of too little (which just means the process will take longer) than using too much (which means a broken crystal and perhaps a cut finger).
I don't want to hear any stories of people getting cut out there, so feel free to wear thin leather gloves (I broke a few crystals while experimenting, and always do it without gloves - no cuts yet :smile:) The thinner the crystal the more gentle you should be (which should go without saying). At this point (I have done about a half a dozen) I am sure to not grip the crystal too tightly or press too hard.
After every 10 strokes or so be sure to test fit the crystal into the bezel and make note of your progress. DO NOT apply more than VERY gentle pressure if it looks like it will go into place - when it is very close to finished it will look like you could give it a push and get it into the bezel, but you will only break the glass and have to start over with a new one. When you get to this point you want to switch to a finer sandpaper and test fit after every few strokes.
There is a bit of art involved - rotating the glass in the bezel (since most bezels are not exactly round, and the glass may not be either) to examine how it is going to fit, perhaps grinding down one side of the crystal a bit more - once again, a bit of practice will tell you what you need to know.
Most important is patience as you near the correct fit - try pushing it into place too hard and you will snap it, grind it too much and you will make it too small and need to glue it in (not the worst thing in the world, but much more satisfying to snap fit it without glue!)
This whole process will only take 5 to 15 minutes if done correctly (even with a crystal several sizes too large).
http://jasongoldman.com/pics/b.jpg
http://jasongoldman.com/pics/c.jpg
http://jasongoldman.com/pics/e.jpg
[This message has been edited by GandalfPC (edited 11-02-2002).]