Helix Angle of Power Screw given Torque Required in Lifting Load with Acme Threaded Screw Calculator

Helix Angle Formula:

\[ \alpha = \arctan\left(\frac{2 \cdot T - W \cdot d_m \cdot \mu \cdot \sec(0.253^\circ)}{W \cdot d_m + 2 \cdot T \cdot \mu \cdot \sec(0.253^\circ)}\right) \]

Torque for lifting load:

Load on screw:

Mean Diameter of Power Screw:

Coefficient of friction:

Helix Angle:

degrees

1. What is Helix Angle of Power Screw?

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

Purpose: It's crucial for determining the mechanical advantage and efficiency of power screws used in lifting applications.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \alpha = \arctan\left(\frac{2 \cdot T - W \cdot d_m \cdot \mu \cdot \sec(0.253^\circ)}{W \cdot d_m + 2 \cdot T \cdot \mu \cdot \sec(0.253^\circ)}\right) \]

Where:

\( \alpha \) — Helix angle (degrees)
\( T \) — Torque for lifting load (Nm)
\( W \) — Load on screw (N)
\( d_m \) — Mean diameter of power screw (m)
\( \mu \) — Coefficient of friction (typically 0.15±5%)
0.253° — Standard thread angle for Acme threads

3. Importance of Helix Angle Calculation

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

4. Using the Calculator

Tips: Enter torque in Nm, load in N, mean diameter in meters, and friction coefficient (default 0.15). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is 0.253° used in the formula?
A: This is the standard thread angle for Acme threads, which have a 29° included angle (0.253° per side).

Q2: What's a typical coefficient of friction?
A: For well-lubricated steel screws, μ ≈ 0.15±5%, but this varies with materials and lubrication.

Q3: How does helix angle affect screw performance?
A: Higher angles increase speed but reduce mechanical advantage; lower angles increase force but reduce speed.

Q4: What if my screw isn't Acme threaded?
A: Use a different calculator as the thread angle (0.253°) would change for other thread types.

Q5: How accurate is this calculation?
A: Accuracy depends on input precision, especially the friction coefficient (±5% typical variation).