Introduction of several screws

Cap screw Cap screw in the past limited to fully threaded fasteners, but this is not standard usage now. Hex head screw Hex Cap screw with the hex bolts Hex hex bolt as the name suggests the head externally threaded fastener designed to use a wrench to turn. In accordance with the ASME standard B18.2.1, Hexagon socket head cap screws (Hex Cap screw) more general large Hexagon bolt (Hex bolt) head high and Rod length tolerance of small, ASME B18.2.1 hex cap screws for attachment to the Hexagon bolts can be used for all places, also contains a large Hexagon bolts are too large to use the place. Socket Cap screw Hexagon socket head screw, also known as Wo TOU screw or Allen bolts (Allen bolt) is a screw with a hexagon-shaped holes in the head, six square (hex key, Allen wrench or Allen key) to insert in the hole can be tightened or loosened. Hexagon screw cheese head screws is the most commonly used, is about 1.5 times of the major diameter of the thread (1960 series), other heads including the surface appearance of round head screw (Bottom head cap screw) and applies to the tapered screw hole grub screw (Countersunk head cap screw). Sink holes