What grinder bit are you using? Like sandpaper, you would want to use a fine grinder bit. When I got my grinder I used the bit that came with it but I've been grinding mostly plates so I haven't had to worry about the chipping edges. I did use it on mirror and it chipped it real bad, but then I read somewhere that it needs a very fine grinder bit to eliminate chipping.

Barb

Yep...crafty is right. The real fine bit works much better.
My first gog looked awful when it was grouted because of all the chips. I get a lot less with the fine one.

Hazie

Use a scrap piece of glass to push against the grinder head when you first start grinding. It kind of "smoothes" the diamonds . Sounds weird but it works.

Check for wear on the bit if you've been using it for tile or haven't adjusted it it in a while.
Keep the water level up, if you see white paste it's not high enough.
Applying to much pressure can also be a problem.

Too much pressure could be the problem and going too fast across your bit. Also some glass like irridecent, has more of a tendancy to chip. Got you new grinder eh?!! What about a pic of the newest addition to your happy family!

Thanks for the advice everyone. I'll take a good look at it (and the manual) tomorrow. NO, CJ, it's not new. Probably got it a year ago; I haven't used it much but it's been working overtime lately. My diamond cuts aren't straight and I have to smooth off the curves I've been getting. I'm trying to improve my cutting skills. Love glass but it doesn't love me.