How much force is needed to cut in half a tough tool steel beam 5 cm wide and 1 cm thick? Theoretically, the cohesion is low. For example, the surface tension of water is 71 mN/m. Some materials are more cohesive. Quicksilver has surface tension of 450 mN/m. Molten gold and copper have over 1 N/m. The cohesion values of solids are less commonly quoted, but I find under 2 N/m for iron. Theoretically, just to separate the atoms, 0,1 N should be enough to cut the width of the 5 cm beam, and just 0,02 N - meaning 2 gf - should cut the 1 cm thickness of the beam. But with practical blades? Metals are often cut by welding, or with metal saws. But chisels intended for metal do exist. What kind of chisel blades are used to cut such sizes of tool steel? And what are the cutting forces needed, in practice?