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

Definition: This calculator determines the optimal drilling speed (RPM) and feed rate (IPM) for High-Speed Steel (HSS) drill bits.

Purpose: It helps machinists and metalworkers achieve efficient material removal while extending tool life.

2. How Does the Calculator Work?

The calculator uses these formulas:

Where:

• \( RPM \) — Spindle speed (revolutions per minute)
• \( SFM_{hss} \) — Surface feet per minute for HSS
• \( D \) — 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 drill diameter, then multiplied by feed per revolution to get inches per minute feed rate.

3. Importance of Proper Speed and Feed

Details: Correct RPM and feed rates prevent tool breakage, reduce heat buildup, improve surface finish, and maximize productivity.

4. Using the Calculator

Tips: Enter the SFM for HSS (default 100 ft/min), drill diameter in inches, and feed per revolution (default 0.010 in/rev). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical SFM for HSS drills?
A: For mild steel: 80-120 SFM, aluminum: 200-300 SFM, stainless steel: 30-60 SFM.

Q2: Why does diameter affect RPM?
A: Larger diameters require slower speeds to maintain the same surface speed at the cutting edge.

Q3: What IPR should I use?
A: Start with 0.001-0.002 in/rev for small drills (<1/8"), 0.003-0.010 for medium, and 0.010-0.020 for large drills (>1/2").

Q4: When should I adjust these values?
A: Reduce for hard materials, deep holes, or poor machine rigidity. Increase for soft materials or when using coolant.

Q5: What's the 3.82 constant?
A: It's the conversion factor (12/π) to convert SFM (feet/min) to RPM for a given diameter (inches).