ISO 2284:2017

Overview

ISO 2284:2017 - Hand taps for parallel and taper pipe threads - General dimensions and marking - defines the geometric and marking requirements for hand taps used to cut pipe threads. The standard covers two tap types: taps for parallel threads (G and Rp series) and taps for taper threads (Rc series), with threads conforming to ISO 7‑1 and ISO 228‑1. It also includes informative annexes on the calculation bases for dimensions (Annex A) and the relationship of designations to the ISO 13399 cutting-tool data schema (Annex B).

Key topics and requirements

• Scope and applicability: Applies to hand taps producing G, Rp (parallel) and Rc (taper) pipe threads in accordance with ISO 7‑1 and ISO 228‑1.
• General dimensions: Detailed nominal sizes and dimensional parameters are provided in Table 1 (parallel taps) and Table 2 (taper taps). These tables specify thread diameters, pitch, thread length and overall tap lengths.
• Shank and driving square: Shank diameters and driving-square dimensions must conform to ISO 237. Tolerances for shank diameters and widths across flats are given (precision and non‑precision tolerance classes).
• Tolerances and thread quality: The document references ISO 5969 for tolerance requirements on the threaded portion (ground thread taps) and aligns with established thread dimension standards.
• Marking: Mandatory shank marking includes:
  • the thread series letter (e.g., G, Rp, Rc)
  • the thread designation (e.g., 3/4, 1/4, 1)
  • Example marks: G 3/4, Rp 1/4, Rc 1. The marker may also append the symbol ISO where full compliance is met.
• Annexes: Annex A describes empirical bases and formulas used to calculate threaded lengths and shank lengths; Annex B maps this standard’s designations to ISO 13399 symbols for data exchange.

Applications

ISO 2284:2017 is used by:

• Tool manufacturers and designers to dimension and mark hand taps for pipe threads.
• Quality and inspection teams to verify tap geometry and marking compliance.
• Procurement and specification writers who need standardized product descriptions for taps.
• Machine shops and maintenance departments that select the correct tap for pipe-threading operations. The standard ensures interoperability, traceability and consistent tap performance across industries that use pipe-threaded connections.

Related standards

• ISO 7‑1 - pipe thread dimensions (pressure‑tight joints)
• ISO 228‑1 - pipe thread dimensions (non‑pressure‑tight joints)
• ISO 237 - shank diameters and driving-square sizes
• ISO 5969 - tolerances for ground pipe-thread taps
• ISO 13399 - cutting tool data representation (mapping in Annex B)

Keywords: ISO 2284:2017, hand taps, pipe threads, parallel threads, taper threads, dimensions, marking, ISO 7-1, ISO 228-1, ISO 237, ISO 5969, ISO 13399.