To say it straight away: I count myself more likely to be people with two left hands. Nevertheless, I wanted to give to it to cut the corners of some 4mm thick float glass plates and ordered after extensive online Compare this glass cutter. Not least because he saw the glass cutter most similar, with which I as a child my father, who was very skilled artisan, had seen work. The long and short of it: In the memory I had: Mark cutting, place a ruler or other device along the cutting edge and press firmly to the glass plate (ie at right angles to the glass plate) onto glass cutter straight and with as a single train to Schneider pull over glass. No sooner said than done - and after that I could actually fabricate with a small hammer to the glass to be removed corner a clean break. My conclusion: For the object described here a useful, well-functioning part.