1. What is a Speed and Feed Calculator for Drilling?

Definition: This calculator determines the optimal rotational speed (RPM) and feed rate (IPM) for drilling operations based on material properties and tool specifications.

Purpose: It helps machinists and engineers optimize drilling operations for efficiency, tool life, and surface finish.

2. How Does the Calculator Work?

The calculator uses two fundamental formulas:

Where:

• \( RPM \) — Spindle speed in revolutions per minute
• \( SFM \) — Surface feet per minute (material-specific cutting speed)
• \( D \) — Drill diameter in inches
• \( IPM \) — Feed rate in inches per minute
• \( IPR \) — Feed per revolution in inches

Explanation: The SFM is converted to RPM based on tool diameter, then multiplied by the chip load (IPR) to determine the linear feed rate.

3. Importance of Proper Speed and Feed

Details: Correct RPM and IPM settings prevent tool breakage, improve hole quality, extend tool life, and optimize machining time.

4. Using the Calculator

Tips: Enter the material's recommended SFM, drill diameter, and appropriate IPR (chip load). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Where can I find SFM values for different materials?
A: Consult machining handbooks or tool manufacturer recommendations. Common values range from 30 SFM (hard steels) to 300 SFM (aluminum).

Q2: What's a typical IPR for drilling?
A: For standard HSS drills, IPR typically ranges from 0.001" to 0.020" depending on material and drill size (default 0.005").

Q3: Why is the constant 3.82 used in the formula?
A: It's the conversion factor from SFM to RPM for a 1-inch diameter tool (12/π ≈ 3.82).

Q4: How does drill material affect calculations?
A: Carbide tools can handle higher SFM values than HSS tools (typically 2-3× higher).

Q5: Should I adjust for deep hole drilling?
A: Yes, reduce both RPM and IPM by 20-50% for holes deeper than 3× drill diameter.