Calculating the size of a spiral staircase

drawing scale 1:

Specify dimensions in millimetres

The height of the stairs H
Diameter of stair D1
Internal diameter D2
Angle of rotation A

Number of steps C
The thickness of the treads Z

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Calculation of spiral stairs

Enter the required dimensions

H - The height of the stairs
D1 - outer diameter
D2 - Internal diameter
C - Number of steps
Z - The thickness of the treads
A - The rotation angle of the stairs


The length of steps in the spiral staircases should not be less than 80 cm
Step width in the central part should not be less than 20-25 cm at the widest part - nor more than 40 cm. Spiral staircase step height can be greater than the height recommended for mid-flight of stairs. Normal step height for straight stairs is 16 cm, for spiral stairs - 18 cm

In the place where the leg begins, step spiral staircase to be about 25-30 cm, on the edge - not less than 30-35 cm. The depth level is quite convenient. Then foot man will be on stage in full, not hanging over the edge.

Step size spiral staircases.

h - length of the stage
W1 - step width in the widest part of
W2 - width of the workpiece stage
α - bank angle step

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zhitov Author of the project: Dmitry Zhitov        © 2007 - 2022
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