these are some instructions that i whipped up rather quickly for someone, and i thought i might as well post them on my site. if you want to know how to score and cut glass into squares or rectangles, perhaps you will find this helpful.

these instructions show me using a tile plier that i modified. you can find a tile plier at a home depot or other hardware or home improvement store, and it will work without the modification for tiles as small as 3/8". anything smaller, and the tool is not as effective without modification.

also, the pics show me using a grid for scoring. i made 3/8" and 1/2" grids in my word processor and printed them out. before that, i used ones that i drew by hand... nothing fancy!

tools and equipment
glass scorer
cork-backed ruler
grid
tile plier
practice glass (i recommend using clear glass, it is inexpensive and easy to work with. please note that in the pics i am using non-glare glass.)

How to hold the glass scorer
Your scorer has a little screw on one side of the cutting end... just remember that the screw always should be up. (image #1)

How to line up the score
Place your clear glass on top of the grid. Lay the ruler on top of the glass, along one of the grid lines. If you have a sheet of glass, you may want to start with cutting the sheet in half, so line up the ruler so that it is on top of the glass, and along a grid line that marks the middle of the glass. (image #2)

How to do the score
If you are right-handed, hold the ruler in place with your left hand, and hold the scorer with your right hand, lining it up against the ruler.... if left-handed, just reverse. While keeping the ruler in place with a bit of pressure, push the scorer up, from the bottom to the top of the glass, using the ruler to keep the scorer along the grid line.

How much pressure to use with the scorer
You want to hear a faint zipping... sort of scratchy sound... but more of a zipping than a scratching. If it sounds real scratchy, then too much pressure. If you don’t hear anything, you may not be putting enough pressure. Either too much pressure or not enough pressure can cause the glass to not break cleanly along your score line. Again, it should give you a soft, zippy-scratchy kind of sound... very hard to explain... but once you get the hang of it, you will know it.

How to break the glass on the score line
Once you have made your score line, you should be able to see it on top of the glass, although sometimes you may have to look very hard. (image #3)

To break it, line up the center of the tile plier head, the part covered with tape, over the score line... the scored surface must be facing up. (image #4) The part of the tile plier that is underneath the glass will put pressure along the score line, from the bottom, while the top part stabilizes it... this will break the glass. You should not have to squeeze the tile plier very hard. If it does not easily break the glass, your score is probably not good... do not squeeze harder! If you are down to cutting the tiles, you can squeeze a littler harder, but if you are working with a sheet of glass, don’t do it! Instead, you may want to turn the glass around and try to break it along the score line from the other side.

If your glass is very big, do not hold the glass too far off your work surface... you may want to hold it so that part of it is resting on the work surface... for support. You should feel like you have control of the entire piece of glass.. best to work with more manageable sizes... like not bigger than 12” x 12”. As you get into cutting tile-sized pieces, you don’t have to worry about this so much.

Practice scoring and breaking until you have some confidence in your skill.

How to cut tiles
To cut tiles of whatever size, what you want to do is to score a grid on top of the glass. It is best to start with a square or rectangle of glass, 6” x 6”, or around there. You can go larger, but may want to wait until you feel very confident about it. Follow the process for scoring, but score along each vertical grid line that your glass covers, moving from the right edge of the glass, to the left. Then, rotate the glass 90 degrees, and repeat the process. This should result in a scored grid on top of the glass. (image #5)

Next, you will start breaking along vertical score lines, again from right to left, resulting in strips (image #6) ... then just break the strips into squares. (image #7)

Cutting Van Gogh, Mirror, or Stained Glass
Cut these types of glass the same way as the plain clear glass. However, art glass has some variance in thickness... this, along with the color and/or backing, as with mirror and van gogh glass, can result in a bit more waste... the breaking of the tiles can be a bit more stubborn. As you become more experienced, you will be more aware of the relative thickness of your glass, and may want to adjust your scoring pressure. Don’t be alarmed if you find that a particular glass is not breaking so cleanly... it may just be a bit thicker. Overall, you should achieve a high degree of success with this technique.