Cutting circles

[CrazyKiln]

  Some advice please. I am having trouble cutting circles. I score the glass with my circle cutter, then turn it over and press down on the score line with the rounded part of my pistol cutter. I have tried then turning the glass back again and pressing down on the score line again, but the glass has broken through the circle. I have tried omitting the second pressing and making 4 score lines (12, 6, 3 and 9 o'clock) from the edge of the glass up to about 1cm from the edge of the circle but the glass is still breaking through the circle. I have watched a couple of videos on you tube and can't see where I'm going wrong. Any advice gratefully received. TIA.

[Zeldazog]

Firstly, practice practice practice.  Get some greenhouse or window glass, it's much cheaper to use than going through Bullseye.

I do the score, turnover, press one side until it's clearly started to run the cut, then flip back over and do the breakout cuts

- but I go closer than 1cm to the circle score.  To be honest, 1cm is quite a distance to break glass without a score line - if you stopped 1cm short of a straight line, you'd find that could go off true also.  I stop my breakout score only a couple of millimetres before the circle score.  Also, I sometimes do my break out cuts at a tangent rather than right angle to the circle score.

Still get errors.  Are you oiling your circle cutter?

It is possible to get a clean circle, but it's taken some doing - last year I was still breaking about half of every circle - especially white ones!  Last Xmas I cut about 30 small ones with my lens cutter, much less breakages, but still a few.  I did these last month, 4 out of 4 worked!  Clear is definitely easier than colours (probably because I use Tekta, which has the smooth side)

Not a grinder in sight!

[CrazyKiln]

I am green with envy for your beautifully cut circle. I am using old window glass at the moment and put just a drop of oil on the glass and drag my circle cutter through the oil. I will try doing my breakout score lines closer. Does the size of the glass I'm cutting from matter, in relation to the size of the circle I'm cutting?
Thanks for your advice - I love this forum and the help given.

[Jane C ♫]

This video: https://www.youtube.com/watch?v=T7dqybxIn7Q&feature=youtu.be

[CrazyKiln]

Thanks very much - I hadn't seen that video. I will give it another go tomorrow.

[Zeldazog]

Old window glass (well, any old glass) can be more prone to running off course anyway - even with straight lines, so that might be making things difficult too!

[Pat from Canvey]

Funnily enough I've just got back from a vitrigraph course at Creative Glass, Rochester with Nathan Sandberg. Each pair had to cut 30 plus circles with slightly increasing diameters (1.5mm) for the cane pull. He advocates using grozing pliers to help break off the waste glass after the breakout score. After I was told to use the flat side of the pliers to the top when using, all went fairly well. At home. I'd used my old circle cutter and found that the score line was a bit suspect so bought a new Silberschnitt one and all went well after that.

[CrazyKiln]

Up bright and early this morning and I've cut my 1st complete circle!!! Now to try it on a piece of Bullseye. Thanks for your help.