In article , mbugg4
@aol.com says...
can any one tell me if possible how to cut a hole in single pain glass
for this is needed for a catflap hope you can help

If it is ordinary window glass then yes, see below. If it is a door or a
window at floor level then probably not since the glass should be
tempered.

You can cut in situ using a compass glass cutter and a lot of care.
However, here's the easy way. Measure the glass as you would for
replacing the pane. Measure the position you want the flap, bearing in
mind that there are limits as to how near the edge a hole can be,
practical limits dependent on the glass cutter's patience and skill.
Then go to a glass seller and get a piece of glass cut with a hole cut
in it. Replace the one at home with this and set the old pane aside in
case you move out or want to get rid of the flap. This is a better way
because you are buying a pane of glass with a hole, if the cutter screws
up it's their problem and they start again. If you or they cut a hole in
situ and the glass breaks you'll have to buy a new pane anyhow.

Colin