1. What is Pitch Diameter?

Definition: Pitch diameter is the diameter of the pitch circle, the imaginary circle that two gears roll on without slipping.

Purpose: It's a fundamental measurement in gear design that determines the gear's size and meshing characteristics.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( PD \) — Pitch diameter (meters)
• \( N \) — Number of teeth (integer)
• \( DP \) — Diametral pitch (teeth per meter, 1/m)

Explanation: The number of teeth divided by the diametral pitch gives the pitch diameter in meters.

3. Importance of Pitch Diameter

Details: Accurate pitch diameter calculation ensures proper gear meshing, smooth operation, and correct speed ratios in gear systems.

4. Using the Calculator

Tips: Enter the number of teeth (must be ≥1) and diametral pitch (must be >0). The calculator will compute the pitch diameter in meters.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between pitch diameter and outer diameter?
A: Pitch diameter is slightly smaller than outer diameter and represents the effective contact diameter for meshing gears.

Q2: How do I find diametral pitch?
A: Diametral pitch is typically specified in gear design or can be calculated as N/PD where N is number of teeth and PD is pitch diameter.

Q3: Can I use this for metric and imperial units?
A: This calculator uses meters (m) for length. For imperial units (inches), use diametral pitch in teeth per inch (1/in).

Q4: What's a typical diametral pitch range?
A: Common values range from 20 to 200 teeth/meter (0.5 to 5 teeth/inch) depending on gear size and application.

Q5: Does this work for helical gears?
A: Yes, but you must use the normal diametral pitch for helical gears, not the transverse diametral pitch.