ISO 7049:2011 PDF

Overview

ISO 7049:2011 defines the characteristics of cross-recessed pan head tapping screws with thread sizes from ST 2,2 to ST 9,5 inclusive. The standard provides dimensional references (Figure 1, Table 1), head and recess types, material and mechanical property references, and rules for designation and acceptance. It replaces the 1983 edition and is intended for manufacturers, purchasers and design engineers specifying tapping screws for reliable fastening.

Key Topics

• Scope: Applies to cross-recessed pan head tapping screws, thread sizes ST 2,2–ST 9,5.
• Dimensions: Detailed dimensions and preferred lengths are given in Table 1 and illustrated in Figure 1. Symbols and dimension descriptions follow ISO 225.
• Head & Recess Types: Specifies pan head types (C, F, R, H, Z) and cross-recess forms. Recess penetration and maximum dimensions are included in the dimensional tables.
• Materials & Mechanical Properties:
  • Steel in accordance with ISO 2702 (heat-treated tapping screws).
  • Stainless steel grades referenced include A2-20H, A4-20H, A5-20H with mechanical properties per ISO 3506-4.
• Coatings & Finishes:
  • Electroplated finishes per ISO 4042.
  • Zinc-flake (non-electrolytic) coatings per ISO 10683.
  • Passivation of stainless fasteners per ISO 16048.
• Tolerances & Acceptance:
  • Product tolerances per ISO 4759-1.
  • Acceptance inspection per ISO 3269.
• Designation: Examples illustrate the required designation format, e.g. "Tapping screw ISO 7049 - ST 3,5 × 16 - St - R - Z".

Applications

ISO 7049 tapping screws are used where self-tapping fasteners are required for sheet-metal and light mechanical assemblies. Practical benefits include:

• Consistent interchangeability across suppliers when screws are specified to the standard.
• Material and finish options for corrosion resistance (stainless grades, coatings).
• Clear designation simplifies procurement and quality inspection.

Typical applications: sheet-metal work, enclosures, electrical assemblies and general mechanical fastening where cross-recess pan-head tapping screws are appropriate.

Related Standards

ISO 7049 cross-references several normative documents that define symbols, threads, recesses, materials and inspection practices. Key related standards include:

• ISO 225 - symbols and dimension descriptions
• ISO 1478 - tapping screws thread
• ISO 2702 / ISO 3506-4 - mechanical properties (steel and stainless)
• ISO 4757 - cross recesses for screws
• ISO 4759-1 - tolerances for fasteners
• ISO 4042, ISO 10683, ISO 16048 - finishes and passivation
• ISO 3269 - acceptance inspection

For procurement and design, reference ISO 7049:2011 together with the listed normative standards to ensure correct dimensions, material selection and quality acceptance criteria when specifying cross-recessed pan head tapping screws.