1. What is Drill Point Length?

The drill point length is the distance from the drill's outer corner to the point where the two cutting edges meet. It's an important measurement for determining drill depth and point geometry in metalworking applications.

2. How Does the Calculator Work?

The calculator uses the drill point length formula:

Where:

• \( \text{Diameter} \) — Drill diameter in inches
• \( \text{Angle} \) — Point angle in degrees (typically 118° or 135° for metal drills)
• \( \tan \) — Trigonometric tangent function

Explanation: The formula calculates the length of the conical tip based on the drill's diameter and point angle geometry.

3. Importance of Drill Point Calculation

Details: Accurate drill point length calculation helps in determining proper drill depth, avoiding drill breakage, and achieving precise hole dimensions in metalworking operations.

4. Using the Calculator

Tips: Enter drill diameter in inches and point angle in degrees. Typical point angles are 118° (standard) or 135° (for harder metals). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the standard point angle for metal drills?
A: 118° is standard for general purpose drilling in mild steel. 135° is used for harder metals as it provides better centering and requires less force.

Q2: Does material affect the point length calculation?
A: The calculation is purely geometric, but material properties determine the optimal point angle which then affects the point length.

Q3: Why is point length important in drilling?
A: It affects drill depth calculations, tool life, and hole quality. Longer points may require more force and are more prone to breakage.

Q4: How accurate is this calculation?
A: The calculation is mathematically precise for perfect conical points. Actual drills may have slight variations due to grinding and wear.

Q5: Can this be used for drill bit sharpening?
A: Yes, knowing the point length helps in maintaining consistent geometry when resharpening drill bits.