What is the standard countersink angle for flat head screws?

The standard ANSI/ASME countersink angle is 82° for inch-series flat head screws. For metric screws, the standard is 90°. Always verify the screw standard before programming to ensure proper seating.

How do I measure countersink depth accurately?

Use a countersink depth gage or a ball-bearing method: place a precision ball bearing of known diameter in the countersink and measure the height above the surface. The countersink depth can be calculated from the ball diameter and measured height.

Can I use a spot drill to create a countersink?

Spot drills are designed for starting holes, not creating countersinks. Their included angle (90° or 120°) differs from standard countersink angles (82° or 90°). Use dedicated countersink tools or chamfer mills for proper geometry and consistent results. ⚡ Calculated for Carbide-Tooling.com High-Performance Series. View Catalog →