ISO 11168:1995

Overview

ISO 11168:1995 specifies the dimensions and technical requirements for socket wrenches for spark‑ and glow‑plugs. It applies to hand‑operated spark‑plug and glow‑plug sockets designed to drive plugs with a hexagon engagement. The standard defines sizing, drive types, test methods and marking to ensure interchangeability, safe operation and consistent quality across manufacturers and service tools.

Key Topics

• Scope and purpose: Standardizes spark‑plug and glow‑plug socket dimensions and technical characteristics for hand operation and hexagon drive.
• Nominal sizes: Covers common socket across‑flats (S) sizes (examples in the standard include 12, 14, 16, 19, 20.8, 22.2 and 25.5 mm).
• Drive forms: Defines acceptable drive/connect interfaces (symbolized I–V), including:
  • Form I: female square drive per ISO 1174
  • Form II: male hexagon drive corresponding to ISO 691
  • Form III–V: pin/through‑hole, cardan/universal, and other manufacturer options
• Mechanical tests:
  • Minimum test torques specified by size (e.g., 12 mm → 42 N·m; 14 mm → 64 N·m; 16 & 19 mm → 100 N·m; 20.8/22.2/25.5 mm → 128 N·m) to verify strength under load.
  • Hexagonal test mandrel hardness requirement: at least 55 HRC, with 4 mm penetration during testing.
  • After applying minimum test torque, no damage must impair socket use.
• Retention device: If fitted, a plug‑retention feature must release the plug between 5 N and 30 N and avoid damage to the plug insulator.
• Marking and designation: Sockets must be permanently marked with the manufacturer name/brand and the across‑flats size. Standardized designation examples are provided (e.g., “Clé à bougies ISO 11168 - 19 - I - 12,5”).
• Dimensional tolerances: References ISO 691 (openings and bit tolerances) and ISO 1174 (square drives) for related dimensional requirements.

Applications

• Tool manufacturers designing and producing spark‑plug and glow‑plug sockets for passenger cars, commercial vehicles and industrial engines.
• Automotive service tool procurement and quality assurance teams specifying compliant sockets for workshops.
• Aftermarket tool suppliers and distributors ensuring compatibility with vehicle plug geometries.
• Design and testing labs performing torque and durability verification on hand tools.

Related Standards

• ISO 691 - Openings of wrenches and bit sockets (metric series)
• ISO 1174 - Drive squares for sockets and machine sockets
• ISO bibliographic references for spark plugs and glow‑plugs (e.g., ISO 1919, ISO 2344, ISO 2345, ISO 2346, ISO 2347, ISO 2704, ISO 2705, ISO 3895, ISO 3896, ISO 6550, ISO 8470)

Keywords: ISO 11168, socket wrenches for spark‑ and glow‑plugs, spark‑plug socket, glow‑plug socket, dimensions, technical requirements, hand tools, test torque, ISO 691, ISO 1174.