I agree with the part of Steve's post that says most people use too much pressure.
Rebecca
Oh, I agree that many people (maybe most) use too much pressure, I just disagree that it has to do with pistols or pencils. People use too much pressure, not because of the type of cutter they use, but because they think it's right.
They've been fed a line of B/S about how a score should sound, and they've started out using lower quality glass. The sound will change with the type of glass used. So there's a right sound for each glass, so it's not a one-sound-fits-all situation.
Some glass scores almost silently, some hisses, some sizzles and some almost crackles, but none of these sounds should be loud, just barely audible.. That's the nature of the glass. Less expensive glass generally, but not always, is more tolerant of heavy pressers. Better glass, again generally but not always, is more particular about how much pressure is used. But, as a general rule, the less experienced glassers press harder than necessary most of the time, and harder than allowable some of the time.
Pressing too hard, particularly on brittler glass, causes chipping, and chips are the harbingers of cracks.
