How to cut a square hole in a sheet of glass.

[berhurt]

I want to cut a rectangular hole in a glass door at home to install a doggy-door. I was wondering if there is any safe/reliable way that I can do this. I have a drill-bit for glass so the bolts won't be a problem. It's just the main hole I'm not too sure about.

I've used a glass-scourer before, but I don't know how well it can be applied to only cutting a section of a piece of glass and not the whole thing...

At the moment I'm thinking of scouring out the rectangle and the diagonals, then drill holes in the corners and the centre, then tap out the glass...the only problem is that I can see the entire thing shattering to pieces...

Any suggestions will be very much appreciated.

 

[Watchmaker]

I think that the way the experts do it is not to have sharp corners but, I may be wrong. I have done it (cat flap) by cutting out a former made of hardboard, sticking it to the glass, and scoring around the edge. With further scoring, into the centre of the piece to be removed, the glass can be tapped gently out. I think that it will depend on the depth of the overlap of the dog door frame, ie, the deeper the better, so that the corner radii are not too acute.

 

[jud1967]

Just a note.

All glass in doors should be toughened glass if so this cannot be cut, and will be identified by a kite mark in the corner.

If not putting a dog flap in annealed glass is not advisable as this will have a tendancy to break easily.

 

[joeb99]

Take the glass out, and replace it with a wooden panel. A dog hitting into a single glazed door panel will end in a £400 vet bill.