Tools have been around since the start of mankind. They may have been perishable or any accessible object that could help do something that humans are physically unable to do themselves; like cut wood, smash hard items, or carve out stone. They may have started out as branches, random stones, or animal bones, but eventually man’s hunting and gathering skills evolved, so did his tools.
Cutting tools, such as the knife, scythe or sickle, are wedge-shaped implements that produce a shearing force along a narrow face. Ideally, the edge of the tool needs to be harder than the material being cut or else the blade will become dulled with repeated use. But even resilient tools will require periodic sharpening, which is the process of removing deformation wear from the edge. Other examples of cutting tools include gouges and drill bits. Here is a fascinating picture of a historical knife made from stone. When compared to the modern knife, its apparent how far we have come.
Tools used to measuring and calculating were developed much later after cutting tools and the wheel. The level, for example helps keep things plumb and level when constructing anything from a large building, to a child’s chair. Keeping things in line is very important to make sure it will function properly, and safely. If cabinets are not level, for example. dishes can fall out and hurt someone. Or if a building is not plumb, things can go awry when trying to construct the top floor and everything is tilted. Accuracy is of the utmost importance.