Bert Byfield wrote in
46.128:

I've heard about scoring the glass on only one side and scoring it
on both sides as the preferred way to cut/break glass. I've done
it both ways. Anyone got any real insight into this matter????
H. R.(Bob) Hofmann

How to Cut Glass

Clean off a portion of a table or workbench and make sure it's flat,
then lay a damp rag over the area. The rag will cushion the glass,
and the moisture will keep it from slipping.

Rest a piece of glass flat on the rag so that it is completely
supported. Then clean the glass with any household glass cleaner.

Measure and mark the glass for your first cut line.

Line up a metal straightedge with your marked line, then shift it
slightly as needed to account for the offset of the glass cutter's
wheel.

If your glass cutter is not the self-oiling type, lubricate the
cutting wheel with a drop of lightweight machine oil.

Now you're ready to score the glass. This creates a weakened area
much like a fault line. You'll be able to snap the glass easily and
cleanly along this line.

Secure the straightedge with duct tape. Hold the glass firmly in
place, then draw the glass cutter along the straightedge with a firm,
smooth stroke that goes from edge to edge. If you do this correctly
you'll hear a subtle but steady scratching sound. You have one chance
to do this right because glass should not be rescored.

Remove the straightedge, flip the glass over, and tap gently on the
back side of the score line with the ball at the end of the glass
cutter. This extends the weakened area through the thickness of the
glass.

Now hang the glass over the edge of your table and tap it lightly to
break it along the scored line.

Make your next cut in the same fashion. Then clean the glass again to
remove any traces of cutting oil.



Google cut & paste. Nice job :-)