Technicals: Hexagon Head Bolt
What is a Hexagon Head Bolt?
Bolt is the term used for a partially threaded fastener (bolt with shoulder/ part plain shank bolt), with a head; designed to be used with a nut and washer.
Bolts are mechanical fasteners with a male thread and a head, designed to be used with a nut or in a threaded hole to create a clamping load. The primary function of a bolt is to connect two unthreaded components together with a nut. Screws have a smooth, unthreaded body part that acts as a pin to hold the connection against lateral shear forces. The use of cylindrical bore screws is uncommon, and generally reserved for hex head screws, which are screwed fully into the head and have a part containing its own thread; the screw must always be turned to mount the connector. Nuts and bolts use a wide variety of head designs, the most common being hexagonal and square; they are designed to work with the tools used to tighten them. In some cases, the head is designed to lock the screw in place, stopping rotation; a wrench or turning device is only needed to turn the mounting nut. More bolts can be used to add increased holding force, depending on the properties and section size of the adjoining components. See the examples below.
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A screw turns into something which has been pre threaded with a tap and a bolt joins several materials or components together from both sides of materials joined. A set screw is fully threaded from beneath the head and a bolt is partially threaded (has a part-plain shank beneath the head). Hexagon head screws and hexagon head bolts are the most popular fastener product and are used with the following thread types:
- Metric Millimetres (mm): European Measurement System,
- British inch ("): British Standard Whitworth (BSW), British Standard Fine (BSF),
- British Association (BA) and,
- American Inch threads: United Coarse (UNC), United Fine (UNF).
Bolts and screws are available in a range of strength classes or grades and materials. Manufacturer's identify the bolt or screw's properties through using letters and/ or symbols and this is a mandatory requirement in the interest of safety and function.
High Strength Friction Grip EN14399
Non-preload hexagon bolting assemblies have to be supplied in accordance with 'British Standards' BS EN 15048. (BAPP PDF)
Preloaded Hexagon bolting assemblies in accordance with BS EN 14399 (BAPP PDF) To adhere to the 'Conformite European', CE marking requirements.
Fasteners will be labelled in accordance with standards and regulatory requirements. The certificates are to prove the material's mechanical properties and certificates to guarantee that the fastener conforms to standards is another way to ensure you are using a fit for purpose fastener. For example
German Institute for Standardisation or Deutsches Institut für Normung or DIN Standards
International Standards Organisation or ISO standards.
DIN 931 Metric Hex Bolts Dimensions
|
Diameter |
Width Across Flat (s) |
Head Height (k) |
Thread Length |
|||||||||||
|
DIN 931 |
ISO 4014 |
DIN 931 |
ISO 4014 |
DIN 931 Length (in MM) |
ISO 4014 Length (in MM) |
|||||||||
|
Min |
Max |
Min |
Max |
Min |
Max |
Min |
Max |
≥125 |
>125≥200 |
≥200 |
≥125 |
>125≥200 |
≥200 |
|
|
M2 |
3.82 |
4.00 |
3.82 |
4.00 |
1.28 |
1.52 |
1.275 |
1.525 |
10 |
- |
- |
10 |
- |
- |
|
M3 |
5.32 |
5.50 |
5.32 |
5.50 |
1.88 |
2.12 |
1.875 |
2.125 |
12 |
- |
- |
12 |
- |
- |
|
M4 |
6.78 |
7.00 |
6.78 |
7.00 |
2.68 |
2.92 |
2.675 |
2.925 |
14 |
- |
- |
14 |
- |
- |
|
M5 |
7.78 |
8.00 |
7.78 |
8.00 |
3.35 |
3.65 |
3.35 |
3.65 |
16 |
22 |
- |
16 |
- |
- |
|
M6 |
9.78 |
10.00 |
9.78 |
10.00 |
3.85 |
4.15 |
3.85 |
4.15 |
18 |
24 |
- |
18 |
- |
- |
|
M8 |
12.73 |
13.00 |
12.73 |
13.00 |
5.15 |
5.45 |
5.15 |
5.45 |
22 |
28 |
41 |
22 |
- |
- |
|
M10 |
16.73 |
17.00 |
15.73 |
16.00 |
6.22 |
6.58 |
6.22 |
6.58 |
26 |
32 |
45 |
26 |
- |
- |
|
M12 |
18.67 |
19.00 |
17.73 |
18.00 |
7.32 |
7.68 |
7.32 |
7.68 |
30 |
36 |
49 |
30 |
- |
- |
|
M14 |
21.67 |
22.00 |
20.67 |
21.00 |
8.62 |
8.98 |
8.62 |
8.98 |
34 |
40 |
53 |
34 |
40 |
- |
|
M16 |
23.67 |
24.00 |
23.67 |
24.00 |
9.82 |
10.2 |
9.82 |
10.18 |
38 |
44 |
57 |
38 |
44 |
- |
|
M18 |
26.67 |
27.00 |
26.67 |
27.00 |
11.28 |
11.7 |
11.285 |
11.715 |
42 |
48 |
61 |
42 |
48 |
- |
|
M20 |
29.67 |
30.00 |
29.67 |
30.00 |
12.28 |
12.7 |
12.285 |
12.715 |
46 |
52 |
65 |
46 |
52 |
- |
|
M22 |
31.61 |
32.00 |
33.38 |
34.00 |
13.78 |
14.2 |
13.785 |
14.215 |
50 |
56 |
69 |
50 |
56 |
69 |
|
M24 |
35.38 |
36.00 |
35.38 |
36.00 |
14.78 |
15.2 |
14.785 |
15.215 |
54 |
60 |
73 |
54 |
60 |
73 |
|
M27 |
40.00 |
41.00 |
40.00 |
41.00 |
16.65 |
17.4 |
16.65 |
17.35 |
60 |
66 |
79 |
60 |
66 |
79 |
|
M30 |
45.00 |
46.00 |
45.00 |
46.00 |
18.28 |
19.1 |
18.28 |
19.12 |
66 |
72 |
85 |
66 |
72 |
85 |
|
M33 |
49.00 |
50.00 |
49.00 |
50.00 |
20.58 |
21.4 |
20.58 |
21.42 |
72 |
78 |
91 |
- |
78 |
91 |
|
M36 |
53.80 |
55.00 |
53.80 |
55.00 |
22.08 |
22.9 |
22.08 |
22.92 |
78 |
84 |
97 |
- |
84 |
97 |
|
M39 |
58.80 |
60.00 |
58.80 |
60.00 |
24.58 |
25.4 |
24.58 |
25.42 |
84 |
90 |
103 |
- |
90 |
103 |
|
M42 |
63.10 |
65.00 |
63.10 |
65.00 |
25.58 |
26.4 |
25.58 |
26.42 |
90 |
96 |
109 |
- |
96 |
109 |
|
M45 |
68.10 |
70.00 |
68.10 |
70.00 |
27.58 |
28.4 |
27.58 |
28.42 |
96 |
102 |
115 |
- |
102 |
115 |
|
M48 |
73.10 |
75.00 |
73.10 |
75.00 |
29.58 |
30.4 |
29.58 |
30.42 |
102 |
108 |
121 |
- |
108 |
121 |
|
M52 |
78.10 |
80.00 |
78.10 |
80.00 |
32.5 |
33.5 |
32.5 |
33.5 |
- |
116 |
129 |
- |
116 |
129 |
|
M56 |
82.80 |
85.00 |
82.80 |
85.00 |
34.5 |
35.5 |
34.5 |
35.5 |
- |
124 |
137 |
- |
- |
137 |
|
M60 |
87.80 |
90.00 |
87.80 |
90.00 |
37.5 |
38.5 |
37.5 |
38.5 |
- |
132 |
145 |
- |
- |
145 |
|
M64 |
92.80 |
95.00 |
92.80 |
95.00 |
39.5 |
40.5 |
39.5 |
40.5 |
- |
140 |
153 |
- |
- |
153 |
|
M72 |
102.80 |
105.00 |
-- |
-- |
44.5 |
45.5 |
-- |
-- |
- |
156 |
169 |
- |
- |
- |
Metric Hexagon Bolt Spanner Sizes DIN931
|
FIXABALL – Specialist Fixings and Fasteners Spanner Sizes METRIC - Hexagon Head Bolts/ Sets |
|
|
Thread Size/ Diameter |
Spanner Size |
|
M3 (3mm) |
5.5mm |
|
M4 (4mm) |
7mm |
|
M5 (5mm) |
8mm |
|
M6 (6mm) |
10mm |
|
M8 (8mm) |
13mm |
|
M10 (10mm) |
17mm |
|
M12 (12mm) |
19mm |
|
M14 (14mm) |
22mm |
|
M16 (16mm) |
24mm |