There lots of videos on running score lines for circles. The most effective for me which leaves a circle which does not need grinding is:
- Allow at least 1/4 inch of glass outside the score line all the way around.
- After making the score to turn the glass upside down over a couple layers of paper towel and applying pressure on the score line at each of the corners to get the runs started then go completely around the score line to ensure it is completely run.
- Next flip the glass back over and run the score line again from the scored side. This will almost always eliminate the tiny flared you may get from only running the scores on the one side.
- Now make 4 relief scores at the thin points of the glass around the circle starting close to the score line without touching it going to the outer edge of the glass.
- Flip the glass over once again & press down on the relief score to cause the glass to fall away from the circle. (You can run 2 score at the same time on opposite sides.)
This system works well for me whether using a circle cutter or free hand cutting. It also works for ovals/ellipses as well.
What other methods do you use which allows you to make a circle without having to grind afterwards?