Thumb screws are designed to be tightened and loosened by hand. They come in a variety of head styles, but each includes an easy-grip head which allows for simple "by-hand" installation.
Nylon 6/6 is a general purpose thermoplastic with outstanding resistance to organic chemicals, acids and alkalis. Nylon wears well against other surfaces; it is readily machinable and may be milled, turned and cut with conventional machine tools. It does exhibit some dimensional swelling in wet applications which should be taken into account with its use. Tensile strength of this material is 12,000 psi (pounds per square inch).
Usually found on thumb screws, a knurled surface on the head gives a better gripping surface, making it easier to tighten or loosen fasteners manually. Common applications for slotted screws include woodworking, although the drive style is not designed to be used with power drivers.
A threaded fastener's size name includes information about the major external diameter (in millimeters), followed by the thread pitch (millimeters per thread), which indicates if it is coarse or fine. Coarse threads are better when working with brittle materials; they are sturdier and are easier to thread and unthread compared to fine. Coarse threading also allows for thicker coatings and platings.