Total cross-sectional area of bolt at root of thread Calculator

Bolt Area Formula:

\[ A_{m1} = \frac{W_{m1}}{\sigma_{oc}} \]

Bolt Load Under Operating Condition:

Stress Required for Operating Condition:

Tolerance Factor:

Bolt Cross-Sectional Area (m²):

With Tolerance (m²):

Definition: This is the smallest cross-sectional area of a bolt at the root of its threads, which determines its strength under tension.

Purpose: It helps engineers determine if bolts can withstand operating conditions without failing.

The calculator uses the formula:

\[ A_{m1} = \frac{W_{m1}}{\sigma_{oc}} \]

Where:

Explanation: The bolt load is divided by the allowable stress to determine the minimum required cross-sectional area.

Details: Proper bolt sizing ensures structural integrity, prevents joint failure, and maintains gasket sealing pressure.

Tips: Enter the bolt load in newtons, operating stress in pascals, and tolerance percentage (default 5%). All values must be ≥ 0.

Q1: Why is the root area important?
A: The root has the smallest diameter and therefore the highest stress concentration.

Q2: What's a typical tolerance percentage?
A: ±5% is common, but this depends on safety factors and application requirements.

Q3: How do I find the bolt load?
A: It's typically calculated based on gasket seating requirements and internal pressure.

Q4: What affects the operating stress value?
A: Material properties, temperature, and safety factors all influence the allowable stress.

Q5: Should I round up the calculated area?
A: Yes, always select the next standard bolt size that meets or exceeds your calculation.