AROUND THE COIL, NOT UP ITS AXIS

Measure the curve
behind the coil.

Calculate an ideal helical cord or wire centreline from diameter, pitch and turns. Add your straight tails, then keep any material allowance separate.

Fractional turns supportedClear diameter references

Define a constant-radius helix

An ideal geometric length. No spring performance, electrical rating, winding-clearance or fabrication approval is calculated.

Diameter and round cross-section

Dimension unit

Converts all five dimension fields.

Measured diameter reference

Defines the number entered below. Changing it reinterprets that number.

Measured diameter

Across the selected reference, not a radius.

Round cord / wire diameter

Required for inside/outside references. Zero is an ideal line only with centreline reference.

Progress along the helix

All dimension entries are in mm.

Axial pitch per complete turn

Centreline advance along the axis for 360°. Not an edge-to-edge gap.

Number of turns

Decimals are allowed: 0.5 is half a turn.

Your additional material

First straight tail

Second straight tail

Separate material allowance · %

Applied to curve plus both tails. This percentage is your choice, not a recommended value.

01 · THE PATH

Follow the centreline

Inside and outside diameters need the round cross-section diameter to locate the centreline. The curve length uses that centreline.

02 · THE TRIANGLE

Unwrap one turn

Circumference and axial pitch are perpendicular legs. Their hypotenuse is one turn’s curve length, multiplied by your turns.

03 · THE EXTRAS

Keep additions visible

Your tails and allowance are separate from geometric length. Read the examples and model limits.