When doing anything more mechanical with 3D Printing, chances are that you will need to use bolts, and other fixings, The M series of fixings are produced to the dimensions in DIN 931. Although the DIN 931 standard has now been withdrawn and superseded by ISO 4014, off-the-shelf parts are generally still manufactured to the older specification.
DIN standard DIN 931 (and ISO 4014) specifies the characteristics, tolerances and variation in form of metric-sized hex head bolts, and covers thread diameters from M1.6 up to and including M160.
Most of the time when doing anything with a 3D printer, you are unlikely to need sizes outside M2 to M10, (and in this range there is no Product grade B), I have included details for Product grade A below.
It is also worth noting that a bolt refers only to a fixing with a partially threaded shank, fully threaded screws are covered in ISO 4017.
This post is supposed to be similar to other reference posts, such as the post on the Bearing numbering system.
DIN 931 Hexagonal head bolt dimensions
| M2 | M2.5 | M3 | M4 | M5 | M6 | M8 | M10 | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Pitch | 0.4 | 0.45 | 0.5 | 0.7 | 0.8 | 1 | 1.25 | 1.5 | |||
| b ref | for shank length ≤ 125 | 10 | 11 | 12 | 14 | 16 | 18 | 22 | 26 | ||
| for shank length > 125 and ≤ 200 | – | – | – | – | 22 | 24 | 28 | 32 | |||
| for shank length > 200 | – | – | – | – | – | – | – | 45 | |||
| c | max | 0.25 | 0.25 | 0.4 | 0.4 | 0.5 | 0.5 | 0.6 | 0.6 | ||
| min | 0.1 | 0.1 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | |||
| da | max | 2.6 | 3.1 | 3.6 | 4.7 | 5.7 | 6.8 | 9.2 | 11.2 | ||
| ds | – | nom = max | 2 | 2 | 3 | 4 | 5 | 6 | 8 | 10 | |
| Product grade | A | min | 1.86 | 2.36 | 2.86 | 3.82 | 4.82 | 5.82 | 7.78 | 9.78 | |
| B | – | – | – | – | – | – | – | – | |||
| dw | Product Grade | A | min | 3.2 | 4.1 | 4.6 | 5.9 | 6.9 | 8.9 | 11.63 | 14.63 |
| B | – | – | – | – | – | – | – | – | |||
| e | Product grade | A | min | 4.32 | 5.45 | 6.01 | 7.66 | 8.79 | 11.05 | 14.38 | 18.9 |
| B | – | – | – | – | – | – | – | – | |||
| k | nom | 1.4 | 1.7 | 2 | 2.8 | 3.5 | 4 | 5.3 | 6.4 | ||
| Product grade | A | max | 1.52 | 1.82 | 2.12 | 2.92 | 3.65 | 4.15 | 5.45 | 6.58 | |
| min | 1.28 | 1.58 | 1.88 | 2.68 | 3.35 | 3.85 | 5.15 | 6.22 | |||
| B | max | – | – | – | – | – | – | – | – | ||
| min | – | – | – | – | – | – | – | – | |||
| kw | – | – | min | 0.9 | 1.1 | 1.3 | 1.9 | 2.28 | 2.63 | 3.54 | 4.28 |
| r | min | 0.1 | 0.1 | 0.1 | 0.2 | 0.2 | 0.25 | 0.4 | 0.4 | ||
| s | – | nom = max | 4 | 5 | 5.5 | 7 | 8 | 10 | 13 | 17 | |
| Product grade | A | min | 3.82 | 4.82 | 5.32 | 6.78 | 7.78 | 9.78 | 12.73 | 16.73 | |
| B | – | – | – | – | – | – | – | – | – | ||
The table above has some extra information in it that is not shown in the first image, this is to do with smaller features relating to the underhead fillet.
ISO 4014 Hexagonal head bolt preferred lengths.
The notes for Figure 1 are as follows:
- a – In accordance with ISO 4753: Chamfered end (CH), but for sizes ≤ M4, as-rolled end (RL) is also allowed.
- b – Incomplete thread u ≤ 2p.
- c – lg,max = lnom – b and ls,min = lg,max – 5P.
- d – Shortest standard length lnom determined with 5d for M5 to M8, for M10, 4d[…]
- e – Greatest standard length lnom ≤ 10d or 500 mm, whichever is the shorter.
| l | Range of standard lengths | |||||||
|---|---|---|---|---|---|---|---|---|
| M2 | M2.5 | M3 | M4 | M5 | M6 | M8 | M10 | |
| 16 | ✓ | ✓ | ||||||
| 20 | ✓ | ✓ | ✓ | |||||
| 25 | ✓ | ✓ | ✓ | ✓ | ||||
| 30 | ✓ | ✓ | ✓ | ✓ | ||||
| 35 | ✓ | ✓ | ✓ | |||||
| 40 | ✓ | ✓ | ✓ | ✓ | ||||
| 45 | ✓ | ✓ | ✓ | ✓ | ||||
| 50 | ✓ | ✓ | ✓ | ✓ | ||||
| 55 | ✓ | ✓ | ✓ | |||||
| 60 | ✓ | ✓ | ✓ | |||||
| 65 | ✓ | ✓ | ||||||
| 70 | ✓ | ✓ | ||||||
| 80 | ✓ | ✓ | ||||||
| 90 | ✓ | |||||||
| 100 | ✓ | |||||||
