Helix Angle of Screw given Effort Required in Lifting Load with Trapezoidal Threaded Screw Calculator

Helix Angle Formula:

\[ \alpha = \arctan\left(\frac{P_{li} - W \times \mu \times \sec(0.2618)}{W + (P_{li} \times \mu \times \sec(0.2618))}\right) \]

Helix angle of screw (rad):

1. What is Helix Angle of Screw?

Definition: The helix angle of a screw is the angle between the thread and a line perpendicular to the screw axis.

Purpose: It's a critical parameter in screw design that affects mechanical advantage and efficiency.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \alpha = \arctan\left(\frac{P_{li} - W \times \mu \times \sec(0.2618)}{W + (P_{li} \times \mu \times \sec(0.2618))}\right) \]

Where:

\( \alpha \) — Helix angle of screw (radians)
\( P_{li} \) — Effort in lifting load (N)
\( W \) — Load on screw (N)
\( \mu \) — Coefficient of friction at screw thread (±5%)
0.2618 — 15° in radians (standard trapezoidal thread angle)

Explanation: The formula calculates the helix angle considering the effort required, load, friction, and thread geometry.

3. Importance of Helix Angle Calculation

Details: Proper helix angle ensures optimal screw performance, efficiency, and load-bearing capacity.

4. Using the Calculator

Tips: Enter the effort in Newtons, load in Newtons, and friction coefficient (±5%). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is the thread angle fixed at 15° (0.2618 rad)?
A: This calculator is specifically for standard trapezoidal threads which typically have a 15° thread angle.

Q2: What's a typical coefficient of friction for screw threads?
A: For steel screws, μ is typically 0.15±5%, but varies with lubrication and materials.

Q3: How does helix angle affect screw performance?
A: Smaller angles provide more mechanical advantage but slower movement, while larger angles allow faster movement with less force multiplication.

Q4: Can I use this for other thread types?
A: No, this calculator is specifically designed for trapezoidal threads. Other thread types require different formulas.

Q5: Why is the result in radians?
A: Radians are the standard angular unit in engineering calculations. Multiply by 180/π to convert to degrees.