A 25-piece drill bit set with sizes from 1 mm to 13 mm, typically in 0.5 mm increments, is a comprehensive metric twist-drill kit.
Specifications
-Size range: 1.0 mm to 13.0 mm in 0.5 mm steps
-Number of bits: 25
-Material: Usually HSS (High-Speed Steel) — some sets use cobalt (HSS-E) for higher heat resistance.
-Standard: Often manufactured to DIN 338.
-Tip angle: Typically 118° or 130°, sometimes with split-point for self-centring.
-Tolerance: Diameter tolerance is commonly h8.
-Shank type: Cylindrical shank (shank diameter = drill diameter)
-Coating (optional): May be plain HSS, black oxide, or coated (e.g., titanium nitride) depending on the set.