Glass Cutter

A glass cutter doesn't actually cut glass, it 'scores' glass with a tiny sharp wheel at the tip. A score is simply a tiny scratch on the surface of the glass. Once you've scored a line you simply apply pressure to it and the glass will break along the score.

Types of Cutters:

  • Glass cutters come in all shapes, sizes and colors. Some glass cutters have a reservoir for oil to lubricate the cutting wheel, others do not. Both kinds make the same score on a piece of glass, so this becomes a matter of personal preference. The cutter pictured above is oiled. An annoying feature of oiled cutters is their spring loaded tip. The entire silver colored tip pushes up into the reservoir to dispense oil. This clumsy feature makes cutting a little more tricky.
  • You'll want to have a glass cutter with a carbide wheel. While the initial expense will be a slightly more, it's well worth the investment because it will last much longer.

How to Use One:

  • Always score standing up. You'll have much more control over the cutter.
  • Holding the cutter: You can hold the cutter any way that feels comfortable, as long as you keep it nearly perpendicular to the glass. Most people hold the cutter the same way they hold a pencil.
  • Score so you can just barely see a scratch on the glass. If you see glass chips flying all over, you're scoring too hard. Here is an example of a horrible score (I pushed as hard as I could).

  • You must always cut from one edge of the glass to another, so plan your cuts in advance.
  • Once you start a score, you can't stop and expect to start again. If you try to pick up where you left off, you will never get the cutting wheel back in it's tiny groove and the break will go shooting off in whichever direction it wants.
Cutting Straight Lines:

  • Start your score an eighth of an inch from one edge and score to an eighth of an inch of another edge, using a ruler if you want.
  • Pay close attention to your score when using a ruler, it's easy to wander away from it.

Cutting Circles:

  • Remember that rule about cutting from one edge of the glass to another? Well, that makes circles a little tricky. It usually takes at least three separate cuts to complete one:
Trace a circle.
Draw a gentle curve to cut along. This will be the first of several.
Carefully cut along the first curve and break off this scrap piece with running pliers or grozing pliers.
Draw another gentle curve and cut it off.
Continue doing this until you are left with your circle. As you can see, it won't be neat at first, but you can grind it to perfection later.

Cutting inside curves:

Cutting an inside curve is tricky because you are cutting a line that begins and ends on the same edge of the glass. Here's how to do it:

Draw an inside curve. If you were to score this and try to break it off, the break would probably shoot off diagonally across the glass.
To get around that, we'll cut a series of smaller, less dramatic cuts.
Score the first line, we'll do these one at a time.
Break out your first chunk with grozing pliers.
Continue scoring and breaking. This last piece is on the big side, you could use either grozing pliers or running pliers to break it out.
These same shapes could easily be constructed out of many smaller shapes soldered together, but using these techniques you can successfully work with larger pieces of glass.