ISO 2936 is the standard cited for hex bit sockets. This page sets out what the standard controls for this part, reproduces the dimensional table supplied against it, and notes the related designations referenced on drawings.
ISO 2936 — Scope
ISO 2936 specifies the dimensional requirements for hex bit sockets.
Material, surface condition and any performance rating are set by separate documents specific to this part family — ISO 898-1 and ISO 898-2, which govern bolt and nut property classes, do not apply here.
Tolerance & Product Grades
Tolerances for hex bit sockets are given as limits on the individual dimensions in the table rather than as a fastener product grade.
Where a general-tolerance class is cited on the drawing instead, it applies to the dimensions not otherwise toleranced.
Dimensions Specified by ISO 2936
| Hex size | Square drive | Mating socket screw | Purpose |
|---|---|---|---|
| 3 mm | 1/4 in | M4 | torque-controlled tightening |
| 4 mm | 1/4 in | M5 | torque-controlled tightening |
| 5 mm | 3/8 in | M6 | torque-controlled tightening |
| 6 mm | 3/8 in | M8 | torque-controlled tightening |
| 8 mm | 1/2 in | M10 | torque-controlled tightening |
| 10 mm | 1/2 in | M12 | torque-controlled tightening |
| 14 mm | 1/2 in | M16 | torque-controlled tightening |
Companion Standards
ISO 2936 controls only the geometry of hex bit sockets. Surface finish is governed by separate finish standards (for example ISO 4042 for electroplating), and corrosion testing by ISO 9227 (neutral salt spray). Mechanical performance is set by the standards specific to this part family, not by ISO 898-1 or ISO 898-2, which apply to bolts, screws and nuts.
When to Specify ISO 2936
Choose ISO 2936 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for hex bit sockets.
