1. What is a Spade Drill Speed and Feed Calculator?

Definition: This calculator determines the optimal rotational speed (RPM) and feed rate (IPM) for spade drill operations.

Purpose: It helps machinists and metalworkers calculate proper drilling parameters to maximize tool life and efficiency.

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 rate in inches per revolution

Explanation: The first formula converts SFM to RPM based on tool diameter. The second calculates feed rate by multiplying RPM by feed per revolution.

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 (typically 0.001-0.010 for spade drills). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical SFM for spade drills?
A: SFM varies by material: 100-150 for aluminum, 60-100 for mild steel, 30-50 for stainless steel.

Q2: Why is the constant 3.82 used?
A: This converts SFM to RPM considering 1 foot = 12 inches and π ≈ 3.1416 (12/π ≈ 3.82).

Q3: How do I determine IPR for my material?
A: Consult tool manufacturer recommendations or machining handbooks (typically 0.003-0.006 IPR for steel).

Q4: Can I use this for other drill types?
A: The formulas work for any rotating tool, but optimal SFM and IPR values differ by tool type.

Q5: What if my machine can't reach the calculated RPM?
A: Use the highest available RPM below calculation and adjust IPM proportionally to maintain chip load.