1. What is Screw Thread Shear Stress?

Screw thread shear stress is the stress experienced by the threads of a screw or bolt when subjected to a force parallel to the thread surface. It's a critical factor in determining the strength of threaded connections.

2. How Does the Calculator Work?

The calculator uses the thread shear equation:

Where:

• \( \tau \) — Shear stress (psi)
• \( F \) — Applied force (lb)
• \( A_{th} \) — Thread shear area (in²)

Explanation: The equation calculates the average shear stress across the threaded area by dividing the applied force by the shear area of the threads.

3. Importance of Thread Shear Calculation

Details: Calculating thread shear stress is essential for ensuring threaded connections can withstand applied loads without failure. It helps prevent stripping of threads in bolted joints.

4. Using the Calculator

Tips: Enter the applied force in pounds and the thread shear area in square inches. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: How is thread shear area determined?
A: Thread shear area depends on thread geometry and can be calculated using standards like ASME B1.1 or obtained from manufacturer specifications.

Q2: What are typical shear stress limits?
A: Limits vary by material, but common steel fasteners typically have shear strengths between 40,000-70,000 psi.

Q3: Does this account for multiple threads?
A: The calculator assumes the input area represents the total shear area for all engaged threads.

Q4: When is thread shear most critical?
A: Thread shear is particularly important in short engagement lengths or when using softer materials.

Q5: How does this differ from bolt shear?
A: Thread shear occurs along the thread surfaces, while bolt shear occurs across the shank diameter.