Overview
ISO 1722:1974 is an International Standard from ISO (Technical Committee ISO/TC 82) that defines extension drill‑steel equipment for percussive long‑hole rock drilling using reverse‑buttress threads. It covers nominal drill sizes from 1 1/2 in to 2 1/2 in (38 to 64 mm) and specifies the basic dimensions, component list, and mating parts needed for interchangeable, safe drilling assemblies. ISO 1722:1974 replaces the earlier ISO Recommendation R 1722:1970.
Key topics and technical requirements
The standard focuses on dimensional and interface specifications to ensure compatibility of components used in percussive long‑hole drilling. Major topics include:
- List of components for extension drill‑steel systems (extension rods, coupling sleeves, bits, threaded connections, etc.).
- Extension rod dimensions and lengths - typical nominal lengths listed (for example 3 050 mm, 3 660 mm and 6 095 mm) and hexagonal bar sizes for different nominal equipment ranges.
- Reverse‑buttress threads - internal and external thread dimensions and pitches for reliable percussive coupling (detailed internal/external diameters and thread geometry are tabulated).
- Coupling sleeves - round or chamfered sleeve dimensions given in metric and inch units to match specified thread sizes.
- Four‑wing bits (X‑design) - nominal bit diameters tabulated (examples shown: 70 mm, 76 mm, 89 mm, 102 mm, 115 mm, 127 mm) with mating thread and length information.
- Hollow hexagonal bars for extension rods - bar cross‑section, eccentricity limits, hole position tolerances and section mass to control weight and balance of rods.
- Reference to related standard ISO 723 for forged collared shanks and chuck bushings.
Applications and who uses this standard
ISO 1722:1974 is intended for organizations and professionals who design, manufacture, specify, buy or maintain drill‑steel components for percussive long‑hole drilling, including:
- Mining and quarrying equipment manufacturers
- Drilling contractors and rig operators
- Equipment procurement and maintenance engineers
- Component suppliers (bits, couplings, rods)
- Standards bodies and quality engineers ensuring interchangeability and safety
Using the standard helps ensure component compatibility across suppliers, reduces downtime from mismatched parts, and supports safe, efficient percussive long‑hole drilling operations.
Related standards
- ISO 723 - Rock drilling: forged collared shanks and chuck bushings for hollow hexagonal drill‑steels.
- ISO 1722:1974 supersedes ISO/R 1722:1970.
Keywords: ISO 1722, rock drilling standard, extension drill‑steel, percussive long‑hole drilling, reverse‑buttress thread, coupling sleeves, four‑wing bits, hollow hexagonal bars.