1. What Are Drilling Speeds and Feeds?

Drilling speeds and feeds refer to the optimal spindle speed (RPM) and feed rate (inches per minute) for drilling operations. Proper speeds and feeds are critical for tool life, hole quality, and machining efficiency.

2. How Does the Calculator Work?

The calculator uses standard machining formulas:

Where:

• \( RPM \) — Spindle speed in revolutions per minute
• \( SFM \) — Surface feet per minute (material specific)
• \( D \) — Drill diameter in inches
• \( ChipLoad \) — Chip load per tooth in inches
• \( Flutes \) — Number of cutting edges on the drill

Explanation: The formulas convert surface speed to rotational speed and then calculate how fast to feed the drill into the material.

3. Importance of Proper Speeds and Feeds

Details: Correct speeds and feeds prevent tool breakage, improve hole quality, reduce heat generation, and maximize tool life. Too slow causes rubbing, too fast causes overheating.

4. Using the Calculator

Tips: Enter SFM based on material being drilled (consult reference charts), exact drill diameter, recommended chip load for the material, and number of flutes on your drill bit.

5. Frequently Asked Questions (FAQ)

Q1: Where can I find SFM values for different materials?
A: Machining handbooks and tooling manufacturer websites provide SFM recommendations for various materials like steel, aluminum, plastics, etc.

Q2: What's a typical chip load for drilling?
A: Chip loads vary by material and drill size but typically range from 0.001 to 0.010 inches per tooth for most materials.

Q3: How does drill coating affect speeds?
A: Coatings like TiN or TiAlN often allow 10-30% higher SFM values compared to uncoated tools.

Q4: When should I reduce calculated speeds?
A: Reduce speeds for deep holes (>3× diameter), hard materials, poor rigidity setups, or when using coolant instead of cutting oil.

Q5: What about peck drilling?
A: For peck drilling, use the same RPM but reduce feed rate by 25-50% to account for the interrupted cutting action.