Selection Advice Views: 19

Reading countersink parameter tables and common symbol meanings: Parameter tables accompany countersinks; understanding them is essential for choosing the right model. Common parameters and symbols: 1) Angle (deg) - the taper angle: 60, 82, 90, 100, 110, 120 degrees; 90 is the most common (GB screws), 82 for ANSI; 2) Head diameter (D, or Ø/φ) - maximum diameter: determines the maximum chamfer size; common φ6, φ8, φ10, φ12, φ16, φ20, φ25, φ30; choose 2-5mm larger than the screw head; 3) Shank diameter (d, shank) - holder diameter: determines the collet; common φ6, φ8, φ10, φ12, 1/4in (6.35mm), 1/2in (12.7mm); must match the machine collet; 4) Overall length (L, OAL) - total length: determines reach; common 50, 60, 70, 80, 100mm; 5) Flute length (L1) - cutting-edge length: determines maximum chamfer depth; 6) Material - HSS (standard high speed steel), HSS-E/HSS-Co (cobalt high speed steel), Carbide; 7) Coating - TiN (gold, titanium nitride), TiCN (blue-gray, titanium carbonitride), TiAlN (violet-black, titanium aluminum nitride), AlCrN (dark gray, aluminum chromium nitride), DLC (black, diamond-like carbon), Uncoated (bright); 8) Flutes (z) - 1, 2, 3, 4 flutes: single-flute cuts with less force; multi-flute is faster; 9) Pilot diameter - for piloted spot facers: must match the pilot hole, e.g. φ3, φ4, φ5, φ6, φ8, φ10; 10) Standard - GB, DIN, ANSI/ASME, JIS, ISO; 11) Tolerance - generally +/-0.02mm size, +/-0.5 degree angle; 12) Hardness - HSS HRC62-64, HSS-E HRC65-67, carbide HRA90+; 13) Max chamfer depth - the largest C value (chamfer width); 14) Suitable materials - steel, stainless, aluminum, copper etc. Table example: 90 deg HSS-E TiAlN countersink φ16 x φ10 x 70mm means: 90-degree angle, cobalt HSS, TiAlN coating, 16mm head, 10mm shank, 70mm overall. Another: piloted spot facer 90 deg HSS-E φ20 x pilot φ8 x φ10 shank means: 90-degree, cobalt HSS, 20mm head, 8mm pilot (for M8 pilot hole), 10mm shank. How to read and choose: 1) angle first - by screw standard: 90 or 82; 2) head diameter - 2-5mm larger than the screw head: M6 head about 11mm - choose φ16; 3) shank diameter - match the machine collet: commonly φ10 or φ12; 4) material - HSS or HSS-E for carbon steel; HSS-E or carbide for stainless; 5) coating - TiAlN generally; AlCrN for stainless; DLC for aluminum/copper; 6) overall length - just enough to reach; too long is weak. Common mistakes: 1) watching head diameter only, ignoring shank - the tool will not mount; 2) watching price only, ignoring material - cheap tools may be standard HSS, wearing extremely fast on stainless; 3) wrong angle - a 90-degree tool on an ANSI 82-degree screw will not seat; 4) head too small - cannot reach the needed size; the head will not sink; 5) too long - weak, vibrates. Reading the table lets you choose right the first time. If the table is unclear, send it to us and we will pick the model. Our countersinks have clear markings - ask us.