Allen Grub Screw
Headless, fully threaded fasteners with internal hex drive and cup point per DIN 916 / ISO 4029. Lock components against rotation or axial displacement on shafts. Graded by hardness (45H steel, 21H stainless) rather than tensile strength.
Specification
#
Standard
DIN 916 / ISO 4029 (EN ISO 4029)
Material
Alloy Steel
Thread
Coarse (standard)
Grade
12.9
Coating
Black oxide
Head Type
Headless (no head)
Drive Type
Hexagon socket (Allen key/hex wrench)
Point Type
Cup point (concave depression)
Dimension
#
Size
Thread Dia (d)
Pitch
Length(L)
Thread Length (b)
M3
2.87-3.00
0.5
3mm - 20mm
Full
M4
3.85-4.00
0.7
4mm - 30mm
Full
M5
4.85-5.00
0.8
4mm - 40mm
Full
M6
5.85-6.00
1.0
5mm - 50mm
Full
M8
7.83-8.00
1.25
6mm - 50mm
Full
- All dimensions in mm, tolerance +/- 0.01 mm. Additional dimensions available on request.
Benefits
#
Grub screws provide a compact, headless shaft-locking solution that eliminates the need for protruding fastener heads in confined assemblies. The cup point creates a controlled indentation in the mating shaft surface, generating a positive mechanical lock that resists both rotational slip and axial displacement under vibration.
The headless design allows complete installation within a threaded bore, making grub screws the standard choice for fixing gears, pulleys, collars, and handles to shafts where external fastener heads would interfere with adjacent components. Hardness class 45H ensures the cup point effectively indents most shaft materials without deformation. For precision instruments and robotics, grub screws offer a simple, cost-effective alternative to keyed connections for light-to-moderate torque transmission and position locking.
Common Applications
#
Grub screws are specified for shaft-locking and component fixation where a headless, fully recessed fastener is required.
- Shaft-to-collar and shaft-to-gear locking
- Pulley and sprocket fixation on shafts
- Knob and handle attachment
- Bearing locknut securing
- Precision instrument adjustment locking
- Coupling and universal joint assembly
- Cam and lever fixation
- Door handle and lockset assemblies
- Bicycle component clamping (seat posts, handlebars)
- Machine tool fixture locking
Read Me
| Standard | DIN 916 / ISO 4029 (EN ISO 4029) |
| Material | Alloy Steel |
| Thread | Coarse (standard) |
| Grade | 12.9 |
| Coating | Black oxide |
| Head Type | Headless (no head) |
| Drive Type | Hexagon socket (Allen key/hex wrench) |
| Point Type | Cup point (concave depression) |
| Size | Thread Dia (d) | Pitch | Length(L) | Thread Length (b) |
|---|---|---|---|---|
| M3 | 2.87-3.00 | 0.5 | 3mm - 20mm | Full |
| M4 | 3.85-4.00 | 0.7 | 4mm - 30mm | Full |
| M5 | 4.85-5.00 | 0.8 | 4mm - 40mm | Full |
| M6 | 5.85-6.00 | 1.0 | 5mm - 50mm | Full |
| M8 | 7.83-8.00 | 1.25 | 6mm - 50mm | Full |
