What's the Matter With My Glass Cutter?

by Penny
(Cary, NC, USA)

I haven't cut glass for about 10 years and am starting on a window. How often should the wheel of the cutter be replaced? I've made one window plus about 3 lamps and a couple of night lights with the one I'm using; I've never changed the wheel.

On my practice cuts, I score the glass but it is not breaking in the right place. I probably need a new wheel but maybe my technique has deteriorated.

Should I get a new wheel or a new head?

Answer
Hi Penny,

You didn't say what kind of glass cutter you are using, but I will assume it's one of the many oil cutter available.

I truly don't think you need a new wheel unless you've been very hard on your cutter. My Toyo Pencil Grip cutter has been going strong for 6 years and I expect it to continue performing for many years to come.

To check your wheel for chips, get a piece of scrap mirror glass. Run a score across the glass. Is the score straight or does it look like a dotted line? If it looks like a dotted line, that means the wheel is chipped and it's time for a new one.

I think you might be pressing too hard. You will run into breaking problems with too much pressure. It's pretty easy to tell if you're pressing too hard. Look at you score as you're running the cutter across the glass. Do you see flakes of glass flying up as you score? Is the score line white? Either one means too much pressure. Lighten up as you score. It really doesn't take all that much pressure to get a good score that breaks correctly.

I'm a great believer in using oil on your cutter wheel. Rather than filling the cutter with oil, put oil in a short (baby food) jar. Dip your cutter in the oil every few scores. Blot the wheel on a paper towel after dipping. You don't want puddles of oil on the glass.

There is a theory among some glass workers that cold glass breaks erratically. I'm talking about extremely cold glass like I have in my unheated Upstate New York studio in the middle of winter. I've not had problem, but I'm a wimp and won't work in the cold!

Lastly, read Cutting Glass and see if there is anything you are or are not doing.

I hope I've helped you with your problem,
Sue