Finding tools is a headache. You have to find the right tool and make it easy to operate. Veteran users can easily pick it up after using it too much. We need to summarize and check the information. Today, we will organize and carry a copy for ourselves:
The hex wrench mainly corresponds to the size of the bolt or nut. At this time, the sizes of bolts or nuts are M3, M4, M5, M6, M8, M10, M12, M14, M16, M18, M20, M22, M24. Wrench specifications from 5.57 to 36.
The hex wrench mainly corresponds to the size of the screw. At this time, the screw size ranges from M3 to M24. The wrench size ranges from 2.5 to 17.
The specific corresponding situations are as follows:
usual format:
A: Metric screw B: American screw C: Imperial screw
A: Metric machine screws: Metric
Ex: M3 x 6 – P P B : M3 machine screw, 6mm long, Phillips, flat head, black plated.
Finish Code: Appearance treatment specification
Head Code: The appearance of the head.
Screw head profile. Cylindrical head. Head down. sink head. Spherical cylindrical head. Pan head. dome head. Hex Head.
Thread Code
Screw model Drive Code: Grooved head, characteristic model
Length Code: screw length (mm)
A-1: Thread Code: Screw type
For metric screws, the screw model is directly marked with the outer diameter of the screw.
For example, M3 means the outer diameter of the screw is 3.00mm.; M4 means the outer diameter of the screw is 4.00mm.
Metric Thread Size x Pitch:
Note: Metric screws are listed behind the screw model, and sometimes the pitch of the screw is indicated.
Such as M3x0.5, M4x0.70, M5x0.8, M6x1.
But because of the standard specification, it is usually not mentioned.
A-2: Length Code: Screw Length:
For metric screws, the length of the screw is directly marked in mm.
The total length of the screw is marked, only the length below the head is calculated, and the height of the head is not included.
But the flat head screw is an exception, the total length of the screw is marked with the height of the head.
A-3: Drive Code/ head cutout, features.
