The Framers Forum

Does anybody have any tips for cutting large sheets of glass with a handheld cutter?

I don't really have any problems when the glass is a bit smaller but when I am cutting larger sheets such as 3ft by 4 ft I often find it wanders off the score line. I was taught only with the smaller sizes and I was taught to lift the edge up and sharply snap between my fingers and thumbs. I find if I start trying to lift the edge of the large sheets up they begin to snap before I get to apply the pressure and end up wandering off the score line.

I have tried twisting the sheet once scored and snapping over the edge of the bench with slightly better results, but I still end up getting it wrong more than I would like. I am cutting on a flat bench as I don't really have the space for a second sloping glass bench.

Any tips are greatly appreciated

Chris

I cut all my glass by hand including 4x3 foot and bigger.

For most smaller sizes, I just use the finger/thumb method. However for bigger pieces, I tend to score the glass, then (easier if you move the sheet so it is hanging over the edge of the bench by 2 inches, I run the t-square under the glass pretty much in line with the score. I tend to find now that by the time the t-square is half way along the score, the glass will break perfectly down the score line. It is the weight of the glass that causes this to happen, so this method won't work for small pieces (not needed to).

I can't remember the last time I had a big piece of glass not cut perfectly using this method, and it is also quick as well.

Hope that helps.

What kind of glass cutter are you using?
I cut all my glass by hand including 60''x40'' sheets. If you are using a proper L square and a decent oil filled glass cutter then you should have no problems.
Remember it's all in the noise, scoring the glass should sound like tearing silk

I am using a fletcher gold oil cutter and a large glass cutting t suare currently. On one hand I keep thinking of getting a wall mounted cutter as I am breaking too much glass at the moment and I hate lowering the large sheets flat onto the workbench. But on the other hand I really want to master cutting by hand first.

If it's veering off the score line then the problem is with the score. It's quite tricky on a long cut to maintain even pressure. You can get a 'gap' in the score. Ideally, you need to do it in one smooth action. No pauses. Could be the glass cutter. Have you tried a different one?

If the score is sound then it should snap along at the lightest touch. On a big sheet the weight of it will help. Just lift with a fingertip where the scoreline meets the edge, and then pull the two halfs apart.

How high is your bench, mine is quite high, but I have a step box under the bench which I pull out and stand on, it is then easier to extend your reach when scoring, so it is a smooth action, help to keep the cutter at the same angle along the full length of the score. Have a look at your local glass merchant's bench, I think you will find they are very low to the ground, again this help with the reach and smooth action.

Handy Tip:

If you are doing a long cut, it's a good idea to tape the T-square/straightedge to the far end of the glass with a tab of masking tape so you don't have to worry about it slipping and you can better concentrate on the cut.

I have a 4 foot long aluminium T square and have placed at intervals along the back the self adhesive material that surrounds the clear plastic domes to go on the back of frames, this material then stops the square from sliding

Ian




..............does that make sense??

If the glass is very cold this may be a problem, try warming it up with a fan heater or hand held dryer before cutting.
Are you consistently experiencing problems ? for how long?
What thickness glass are you cutting ?

I would say the problem was definitely worse recently with the cold weather. My workshop is very cold so I did wonder if this could be part of the problem as the glass just felt really brittle. Even when the workshop was a bit warmer though I still had a few too many breakages. I am using 2mm glass by the way.

I will definitely try the tips with the T-square because this slipping right at the end of the cut has been a problem in the past.

Thanks Steve for the tip about the step box. My workbench is quite high and it is hard leaning all the way across at times. I did think of building one for my mount cutter as I often struggle when trimming down the board sizes and I have to reach to the other side. I hadn't considered this for the glass but will give it a try.

Does anyone have any tips on the best way of putting the large glass sheets down on a flat bench? I try to lower them down slowly but find myself holding my breath at times as the glass begins to flex in the middle. At the moment I am using the front edge of the bench to support it until its almost flat and then slide it along.

I have a carpet tucked away in the corner that is brought out for cutting sheets of glass.
I just place it on the floor then use a 5ft T square, score the glass using a SILBERSCHNIT cutter
then just run a steel rule under the score and hey presto two pieces of straight edge glass.

In the beginning it was 1 in 3 that went wrong but now I think I have the knack (or luck) and all seem ok

I have a wall-mounted glass cutter that I inherited when I started framing, but I've never mastered it properly.
So I've been lowering a piece of chipboard onto the floor and cutting my glass on that. I never have any problems putting the glass down on it and I can lean over and get one smooth cut every time.
Probably not ideal for health and safety putting it on the ground, but I'm just in a workshop myself and it's working for me like that for now.
One day I'll spend a bit of time and get the wall mounted one working properly.

For laying the glass on your bench
1. Make sure bench is clear, free from bits of grit,dust etc(brush it)
2. Make sure there are no loose job sheets, photos,paper anythings(they can get blown away)
3. Lift the glass onto the edge of the bench(nearest you), start lowering it........squeeze your cheeks , then let it go. This will create an air cushion under the glass which will allow it to drop without harm, of course if the glass has a weak point(chip on the edge etc) it may split there, but it's quite rare these days to get flawed sheets.

I only use this method on the larger sheets(60"x40") as i cannot keep hold while lowering it, but it will work just fine for 4'x3' sheets, until you build your glass handling confidence.
Also i would get a proper glaziers L square, much better than a T square (in my opinion)

And i'll say it again, you will know by the noise if your score is equal along the length

Good Luck

Don't hold the sheet by the corners. The corner can snap off leaving a a little bit in your hand and the rest of it out of control.

Don't ask.......

I've got an old C & H Advantage Pro 48" mount cutter, and I cut all my glass on that, (up to 4' x 3' - I haven't needed/got the bottle for 60 x 40) . I just slip the glass in as if it were mount board and run a standard glass cutter along the edge of the pressure plate. Takes care of the squaring and the measuring, and there's nothing movable like a square.