1. metric thread (Ren triangle)
Met lace widely used system in Vietnam and many other countries around the world. Technical characteristics of this type of lace set forth in ASME B1.13M-2005 (compatible with ISO 68 to ISO standard profile and 965/1 lace on lace tolerances).
Of metric threaded bolt is determined by the capital letter M, followed by the diameter can be determined more by the steps lace. If it can not be implied lace step defaults coarse lace. Metric thread size is measured in millimeters and is specified in ISO 2247-77 to lace big step and TCVN 2248-77 to lace small steps. (Figure 4.8). Determine diameter, threaded steps and basic dimensions of the ISO metric thread 2248_78 see Table 4:42.
Step Lace is the distance between two adjacent peaks lace
Ren International Standard System
Step by threaded fasteners, the system is divided into steps Met rough and smooth step in which coarse lace prioritized steps used in normal joints.
2. REN SYSTEM INCH (Unified Thread - UN)
(Used 3 agreement between Britain, the US, Canada)
The format of the Unified Inch thread lace
Unified Coarse Thread - UNC
UNC is the kind of coarse lace step is most widely used for joints with low tensile strength and quick assembly requirements on materials with low durability as cast iron, carbon steel, copper, aluminum.
Unified Fine Thread - UNF
UNF threaded type of fine steps, to be used for the joints require high durability or thin-wall joints and assemble approximately short. Also, thanks to the small angle of elevation lace, lace UNF also in the case of tuning the working length of the thread.
Unified Extra Fine Thread - UNEF
UNEF is kind of very fine lace step, used when thickness smaller joints thickness UNF threaded joints.