Unfortunately you are not actually holding these tools correctly to get them to do the jobs they are meant to. Ergonomically they are made to not strain the hand. Try and hold them at the end where the curve is, by holding them as far as possible to the end you will get way more leverage and in doing so do not have to press so hard. The pointed side of the Side bite nippers are meant to be held with the point in the direction of the cut and your opposite thumb and forefinger presses with the same pressure as the tool. This allows the cut to travel in a straight line. The Chisel nippers are for chiseling more than cutting. My favourite nippers are the 7″ Starrett nipper, great leverage and adjustable cutting blades for different thickness of tesserae, they cut Smalti, Marble, Ceramic and stone, effortlessly and accurately.
