Hex / Allen vs. Slotted
Comparing 2 standards across 9 specifications. 9 key differences identified.
The Hex drive (Allen socket / Internal Hexagon, standardized under ISO 4026 and DIN 912) is a 6-sided symmetrical polygonal drive recess developed in the early 1900s by William G. Allen. Widely used in socket head cap screws, bicycle components, and flat-pack furniture, it provides high clamping torque with compact cylindrical head profiles.
The Slotted drive (Flat Head / Flat Blade) is the original single-slot fastener drive geometry standardized under ISO 2380 and DIN 963. Operated with a flat screwdriver blade, it features no inherent centering or cam-out retention, making it susceptible to tool slippage and strictly limited to manual assembly and decorative restoration.
Specification Comparison Table
9 Parameters| Parameter / Spec | ||
|---|---|---|
|
Standard Specifications
|
ISO 4762 / DIN 912 (Socket head cap screws) / ASME B18.3 | ISO 2380 (Screwdrivers) / DIN 963 / ASME B18.6.3 |
|
Drive Geometry
|
Symmetrical 6-sided internal hexagon socket | Single linear rectangular slot through head center |
|
Cam-Out Tendency
|
Low (Requires axial insertion depth; strips if bit is worn or undersized) | Extremely High (Tends to climb up and out of slot under torque) |
|
Metric Standard Sizes
|
1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 6.0, 8.0, 10.0, 12.0, 14.0, 17.0 mm | — |
|
Imperial Standard Sizes
|
0.050", 1/16", 5/64", 3/32", 1/8", 5/32", 3/16", 1/4", 5/16", 3/8" | — |
|
Primary Applications
|
Machine tools, bicycle components (4/5/6mm), 3D printers (2.5/3mm), flat-pack furniture | — |
|
Self-Centering Capability
|
— | None (Driver freely slides laterally out of slot) |
|
Power Tool Suitability
|
— | Unsuitable (High risk of workpiece scratching / bit slippage) |
|
Primary Modern Applications
|
— | Antique furniture restoration, electrical switch wallplates, plumbing fixtures |