1. What is a Drill Speed and Feed Calculator?

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

Purpose: It helps machinists and metalworkers select appropriate drilling parameters to maximize tool life and machining efficiency.

2. How Does the Calculator Work?

The calculator uses two fundamental formulas:

Where:

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

Explanation: The SFM is converted to RPM based on tool diameter, then multiplied by the feed per revolution to determine the linear feed rate.

3. Importance of Proper Speed and Feed

Details: Correct RPM and IPM settings prevent tool breakage, reduce heat buildup, improve surface finish, and optimize material removal rates.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Where do I find SFM values?
A: SFM varies by material (e.g., 100-300 for aluminum, 30-80 for steel). Consult machining handbooks or tool manufacturer recommendations.

Q2: What's a typical IPR for drilling?
A: Common range is 0.001-0.010 in/rev, with smaller drills requiring smaller feeds. Carbide drills can often use higher feed rates.

Q3: Why is the constant 3.82 used?
A: This converts SFM (feet/min) to RPM considering diameter in inches (12/π ≈ 3.82).

Q4: How does drill material affect calculations?
A: HSS drills use lower SFM than carbide. Always use SFM appropriate for your specific tool material.

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