ISO 10899:1996

Overview

ISO 10899:1996 specifies technical requirements for high-speed steel two‑flute twist drills with either cylindrical or Morse‑taper shanks. It covers dimensional tolerances, material and hardness requirements, surface finish, marking and test/measurement methods for drills used in metalworking (excluding roll‑forged drills and do‑it‑yourself/woodworking drills). The standard provides a consistent basis for purchasers and manufacturers to agree special‑purpose drill specifications.

Key Topics

• Scope and applicability: Two‑flute HSS twist drills (cylindrical or Morse taper shanks); not for roll‑forged or woodworking drills.
• Dimensions & tolerances: Drill diameter measured across lands; back taper permitted (typically 0.02%–0.08% over flute length; total back taper ≤0.25 mm; smaller diameters may be parallel). Overall and flute lengths follow relevant dimensional standards; length tolerances per ISO 2768-1.
• Radial runout: Tolerances calculated from a formula that depends on drill diameter and overall length (runout tolerance expressed as a base value plus a term proportional to L/d). No runout tolerance stated for drills d < 2 mm.
• Web and cutting geometry: Minimum web thickness, web symmetry, land width, relative lip heights, flute spacing and point angle are all specified with limits or measurement methods (point angle for general purpose drills typically 118° ± 3°; helix angle by agreement).
• Materials & hardness: Cutting portion must be designated HSS per ISO 11054. Typical Vickers hardness ranges given:
  • HSS: about 780–900 HV
  • HSS‑E: about 820–950 HV Shank hardness minima specified (solid HSS shank ≥240 HV; welded shank ≥170 HV). Knock‑out tang on Morse tapers (nom. diameter ≥10 mm) minimum hardness noted.
• Surface finish & marking: Surface roughness Ra limits are provided by drill part and size. Marking required for drills d ≥ 4 mm (diameter, HSS grade, manufacturer); smaller drills marked on packaging.

Applications

ISO 10899 is used by:

• Tool manufacturers to design and qualify two‑flute HSS twist drills.
• Purchasing/specification teams to define drill acceptance criteria and supplier contracts.
• Quality inspectors and metrology labs for dimensional and hardness testing.
• Machining and tooling engineers selecting drills for production drilling, reaming preparations, and specialty drilling where consistent geometry and hardness are critical.

Keywords: ISO 10899, high‑speed steel two‑flute twist drills, technical specifications, drill dimensions, radial runout, web thickness, hardness, marking, drill tolerances.

Related Standards

• ISO 5419 - Twist drills: terms and definitions
• ISO 11054 - Designation of HSS groups
• ISO 296 - Machine tool tapers (Morse tapers)
• ISO 286-2, ISO 2768-1, ISO 6507-1 - referenced for tolerances and hardness testing