Overview
ISO 12260:2016 specifies the dimensions for a family of aerospace pan‑head screws: internal offset cruciform (ribbed or unribbed) drives, stepped shank, with short or medium length MJ threads, made of metallic material (coated or uncoated) and with strength classes less than or equal to 1 100 MPa. Dimensions and tolerances are given in millimetres and apply after any surface coating but before the application of lubricant. The standard supports the compilation of aerospace product standards and is the second edition (minor revision) of the original 1996 document.
Key Topics
- Screw configuration and dimensions: detailed dimensional requirements for pan head screws with internal offset cruciform drives and stepped shanks; figures and tables (e.g., Figure 1 and Table 1) provide nominal sizes and limits.
- Thread series: short and medium MJ thread forms are covered in accordance with aerospace thread conventions.
- Materials and finishes: applies to metallic screws, coated or uncoated.
- Strength classes: applies specifically to fasteners with strength classes ≤ 1 100 MPa.
- Measurement units and timing: dimensions/tolerances are expressed in millimetres and apply after coating, before lubrication.
- Form and position tolerances: referenced to ISO 7913 for tolerances of form and position.
- Reference tolerance systems: tolerances for linear sizes use the ISO code system (see ISO 286‑2).
Applications
ISO 12260:2016 is intended for organizations involved in the design, manufacture, procurement and quality assurance of aerospace fasteners. Typical users include:
- Aerospace fastener designers and engineers specifying pan‑head MJ screws for assemblies
- Manufacturers and tooling suppliers producing pan‑head screws with internal offset cruciform drives
- Procurement and supply chain teams ensuring purchased fasteners meet aerospace dimensional standards
- Quality control and inspection personnel verifying dimensions and tolerances (post‑coating, pre‑lubricant)
- Standards committees and technical authors compiling aerospace product standards
Practical use cases include specifying interchangeable fasteners for airframe and aircraft component assemblies, ensuring consistent fit and performance across suppliers, and defining inspection criteria for production and incoming inspection.
Related Standards
Normative and closely related references cited in ISO 12260:2016:
- ISO 286‑2 - tolerance classes for holes and shafts
- ISO 3353 (all parts) - lead and runout threads
- ISO 5855‑2 - MJ threads limit dimensions for bolts and nuts
- ISO 7913 - tolerances of form and position for aerospace bolts/screws
- ISO 14275 / ISO 14276 - internal offset cruciform drive specifications
Keywords: ISO 12260, aerospace screws, pan head screws, MJ threads, internal offset cruciform, stepped shank, fastener dimensions, aerospace fasteners standard, tolerances.