Hex Socket Bolt Standard Specification
Aug 07, 2026
Hex socket bolts are widely used standard fasteners in industrial assembly, civil furniture and mechanical equipment. With the development of modern industry, hex socket bolts have become indispensable basic fasteners for lightweight and precision assembly. Featuring easy installation, reliable locking, neat appearance and strong compatibility, they are extensively applied in equipment assembly, furniture installation and precision machinery connection scenarios, such as computer desks, cabinets and precision instruments.
This document sorts out standard dimensional parameters of commonly used hex socket bolts. All data are obtained through manual sampling tests of bulk batches and allow reasonable minor errors. The actual dimensions shall prevail over physical products. Please contact customer service if you need a complete and accurate specification data sheet.
1. Specification Naming Rule
The specification of hex socket bolts is uniformly marked by nominal diameter × shank length (D×L).
Example: M4×20 refers to a nominal thread diameter of 4mm and an effective shank length of 20mm.
Note: All dimensions below are in millimeters (mm). The data are manual sampling test values with reasonable tolerance errors, only for selection reference. Actual assembly shall be subject to physical products.
2. Standard Dimensional Parameter Table of Common Hex Socket Bolts
Parameter Description: d = Nominal Diameter, P = Pitch, dk = Maximum Head Outer Diameter, k = Head Height, S = Hexagon Width Across Flats
|
Nominal Diameter d |
Pitch P |
dk(max) |
dk(min) |
k(max) |
k(min) |
S(max) |
S(min) |
|
M1.4 |
0.3 |
2.74 |
2.46 |
1.26 |
1.36 |
1.32 |
0.6 |
|
M1.6 |
0.35 |
3.14 |
2.86 |
1.46 |
1.56 |
1.52 |
0.7 |
|
M2 |
0.4 |
3.98 |
3.62 |
1.86 |
1.56 |
1.52 |
1.0 |
|
M2.5 |
0.45 |
4.68 |
4.32 |
2.36 |
2.06 |
2.02 |
1.1 |
|
M3 |
0.5 |
5.68 |
5.32 |
2.86 |
2.58 |
2.52 |
1.3 |
|
M4 |
0.7 |
7.22 |
6.78 |
3.82 |
3.08 |
3.02 |
2.0 |
|
M5 |
0.8 |
8.72 |
8.28 |
4.82 |
4.095 |
4.02 |
2.5 |
|
M6 |
1.0 |
10.22 |
9.78 |
5.70 |
5.14 |
5.02 |
3.0 |
|
M8 |
1.25 |
13.27 |
12.73 |
7.64 |
6.14 |
6.02 |
4.0 |
|
M10 |
1.5 |
16.27 |
15.73 |
9.64 |
8.175 |
8.025 |
5.0 |
|
M12 |
1.75 |
18.27 |
17.73 |
11.57 |
10.18 |
10.025 |
6.0 |
|
M14 |
2.0 |
21.33 |
20.67 |
12.57 |
12.21 |
12.032 |
7.0 |
|
M16 |
2.0 |
24.33 |
23.67 |
15.57 |
14.21 |
14.032 |
8.0 |
|
M18 |
2.5 |
27.33 |
26.67 |
17.57 |
14.21 |
14.032 |
9.0 |
