Three screws Classification

Three screws Classification

Three screws Classification

The main categories including ordinary screw screws, tapping screws and three expansion screws.

Cap screw has a head screw fasteners in the past limited the whole tooth, but this is not standard usage.

Hex cap screw hexagon head screws with large hexagon head bolt Hex bolt hexagonal type definition for the external threaded fasteners, designed to use the wrench turning. According to ASME B18.2.1 standard hexagonal head screws (Hex cap screw) the more general large hexagon bolts (Hex bolt) head up high and rod length tolerance is small, so ASME B18.2.1 hex screws hex bolts for installation in all that can be used place, also contains large hexagon bolts are too large to use place.

Hexagon head screws Socket cap screw also known as Aaron Wotou screws or bolts (Allen bolt), is a hexagonal head screw inside the hole to six Square (hex key, Allen wrench or Allen key) into the hole before tightening or loosening. Hexagon is the most commonly used cheese head screws, the first major thread diameter of about 1.5 times the diameter (1960 series), and other head shape including the surface appearance of the round head screws (Bottom head cap screw) and screw holes for tapered flat head screws (Countersunk head cap screw). Sink hole design allows the screw head does not need to be fixed on the outside surface of the object can also rotate, and therefore more use of small surface, the traditional place inconvenient to use wrenches.

Machine Screw Machine screw diameter generally less than ¼-inch screws (4 # ~ 12 #), usually by a screwdriver