1. What is a 100 Degree Countersink?

A 100 degree countersink is a conical hole cut into a manufactured object, typically used to allow the head of a countersunk screw to sit flush with or below the surface. The 100 degree refers to the included angle of the cone.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Diameter \) — The diameter of the countersink (in inches)
• \( 50° \) — Half of the countersink angle (since 100° is the included angle)

Explanation: The formula calculates the depth of the countersink based on its diameter and the 100 degree included angle.

3. Importance of Countersink Depth

Details: Proper countersink depth ensures screw heads sit flush with the material surface, providing a smooth finish and proper fastener seating.

4. Using the Calculator

Tips: Enter the diameter of the countersink in inches. The value must be greater than 0.

5. Frequently Asked Questions (FAQ)

Q1: Why 50° in the formula when it's a 100° countersink?
A: The 100° is the included angle (the total angle of the cone). The formula uses half this angle (50°) for the trigonometric calculation.

Q2: What's the most common countersink angle?
A: While 82° is most common for flat head screws, 100° countersinks are used in specific applications, particularly in aerospace.

Q3: How accurate does the depth need to be?
A: For most applications, ±0.005 inches is acceptable, but critical applications may require tighter tolerances.

Q4: Can I use this for metric measurements?
A: The formula works for any unit as long as diameter and depth use the same unit. Just enter diameter in mm for mm depth.

Q5: Does material affect the calculation?
A: The calculation is purely geometric. Material properties may affect the actual machining process but not the theoretical depth.