How to mark Metric size fasteners and Inch size fasteners?
Apr 30, 2023
The bolts and screws should be marked in the following order:
nominal size；thread pitch； product length； product name； and material；
for example, M8-P1.25×30mm hexagon screw Grade 5.
The nuts should be marked in the following order: nominal size, thread pitch, product name, and material, for example, M8-P1.25 hexagon nut Grade 5.
For fasteners in inch size, they should be marked in the following order:
nominal size (fraction or equivalent decimal),
number of threads per inch and coarse/fine thread designation,
product length (fraction or equivalent decimal),
product name, and material.
UNC represents coarse thread, UNF represents fine thread, and UNEF represents an extra fine thread.
