Basic content of hexagonal head bolts


Hexagonal head bolts are divided into two types: external hexagonal bolts and internal hexagonal screws.

According to the force distribution method of the connection, there are ordinary and hinged holes. The bolts used for hinged holes should match the size of the holes and be used when subjected to lateral forces. Generally, countersunk heads are used in areas that require a smooth surface after connection, such as hexagonal heads, round heads, square heads, countersunk heads, etc., because countersunk heads can be screwed into the parts. Round heads can also be screwed into the parts. The tightening force of square heads can be larger, but the size is large. Hexagonal heads are the most commonly used.

In addition, to meet the need for locking after installation, there are holes on the head and the rod, which can prevent the bolt from loosening when subjected to vibration.

brief introduction

Hexagonal head screws and large hexagonal bolts, as the name suggests, are externally threaded fasteners with a hexagonal head, designed to be turned with a wrench. According to the ASME B18.2.1 standard, hexagonal head screws have a smaller tolerance for head height and stem length compared to regular large hexagonal bolts. Therefore, ASME B18.2.1 hexagonal head screws are suitable for installation in all areas where hexagonal bolts can be used, as well as in areas where large hexagonal bolts are too large to be used.

The outer edge of the screw head of an internal hexagonal screw is round, with a concave hexagon in the middle, and a hexagonal screw is the commonly seen type of screw head with hexagonal edges. The hexagonal screwdriver looks like a “7″. It is made by cutting two sections of a hexagonal steel bar and bending it to 90 degrees to form an hexagonal screwdriver. It is sold in hardware tool stores.

The hexagonal screwdriver is not a so-called “mobile phone specific screwdriver”. Mobile phone specific screwdrivers can be purchased from repair tool stalls in the electronic market.

Internal hexagonal screws are commonly used in machinery, mainly due to their advantages such as easy fastening, disassembly, and resistance to slipping. Internal hexagonal wrenches are usually bent at a 90 ° angle, with one end long and the other short. When using the short end to screw, holding the long end can save a lot of force and better tighten the screw. The long end has a rounded head (similar to a spherical hexagonal cylinder) and a flat head. The round head can be easily inserted and removed at an angle, and can be installed in areas where it is not convenient to use a wrench. The manufacturing cost of the outer hexagon is much lower than that of the inner hexagon, and its advantage is that the screw head (where the wrench is subjected to force) is thinner than the inner hexagon, and in some places, it cannot be replaced by the inner hexagon. In addition, machines with low cost, low power intensity, and low precision requirements use much fewer internal hexagonal screws than external hexagonal screws.

Internal hexagonal head screw, also known as socket head screw or Allen bolt, is a screw with a hexagonal inner hole on the head, which can only be tightened or loosened after being inserted into the inner hole with a hexagonal ruler. The most commonly used hexagon socket head screws are cylindrical head screws, with a head diameter of approximately 1.5 times the main thread diameter (1960 series). Other head types include half round head screws for aesthetically pleasing surfaces and flat head screws suitable for tapered screw holes. The countersunk design allows the screw head to rotate without being exposed on the surface of the fixed object, so it is often used in areas with smaller surfaces that are inconvenient for traditional wrench operators.

Post time: Jun-28-2024