Clearance between Shaft and Stuffing Box if Shaft Diameter is Greater than 100mm Calculator

Clearance Formula:

\[ c = 2.5 \times \sqrt{d_{shaft}} \]

Nominal Clearance (mm):

Minimum Clearance (mm):

Maximum Clearance (mm):

1. What is Clearance between Shaft and Stuffing Box?

Definition: This calculator determines the recommended clearance between a shaft and its stuffing box when the shaft diameter exceeds 100mm.

Purpose: It helps mechanical engineers and maintenance professionals ensure proper sealing and prevent shaft damage during packing operation.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ c = 2.5 \times \sqrt{d_{shaft}} \]

Where:

\( c \) — Clearance between shaft and stuffing box (mm)
\( d_{shaft} \) — Diameter of the shaft (mm), must be ≥100mm

Explanation: The formula provides a clearance value that accounts for shaft expansion, vibration, and packing compression during operation.

3. Importance of Proper Clearance

Details: Correct clearance prevents excessive packing wear, reduces shaft scoring, and maintains effective sealing while allowing for thermal expansion.

4. Using the Calculator

Tips: Enter the shaft diameter in mm (must be ≥100mm) and tolerance percentage (default ±5%). The calculator provides nominal, minimum, and maximum clearance values.

5. Frequently Asked Questions (FAQ)

Q1: Why is there a minimum shaft diameter of 100mm?
A: The formula is specifically designed for larger shafts where clearance becomes more critical for proper packing performance.

Q2: What does the tolerance percentage represent?
A: The tolerance accounts for manufacturing variations and operational factors, providing a range of acceptable clearances (±5% by default).

Q3: When would I adjust the tolerance?
A: Adjust tolerance based on specific application requirements, operating conditions, or manufacturer recommendations.

Q4: Does this apply to all types of packing?
A: This provides a general guideline; specific packing materials may require adjustments based on their compression characteristics.

Q5: How does shaft speed affect clearance?
A: Higher speeds may require slightly larger clearances to accommodate greater thermal expansion and dynamic effects.