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Total Rise Tread Depth at ? Stair tread codes state that each tread will have a minimum tread depth at specified measurement from narrow edge of tread. CHECK LOCAL CODES (See tread diagram) ? Ideal Rise is the rise you'd prefer. Actual Rise is calculated so that all rises fit evenly into Total Rise, at nearest to Ideal Rise. Ideal Rise Widen Tread ? Widen and overlap tread for balusters etc - Widened treads must overlap to form correct geometry   Actual Rise Draw Chords Color Inside Radius Tread Numbers Tread Length Feet Inch ? Treads in Rotation over 360° are shown inset in diagram for clarity Rotation °

Spiral Stair Geometry - Inch Handrail True Radius Calculator Scale ? Treads in Rotation over 360° are shown inset in diagram for clarity Rotation Inside Radius

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Running Measurements explanation Not including Tread Widening

Inside Stringer = tread points winding up and around INSIDE of stairs from top of first rise to upper floor.

Outside Stringer = tread points winding up and around OUTSIDE of stairs from top of first rise to upper floor.

Inside Plumb = tread points vertically (plumb).

Inside Level = tread points around INSIDE LEVEL, (or flat, as marked AROUND a circle on the floor.)

Running Measurements:

Inside Stringer Mark-out

Outside Stringer Mark-out

Inside Plumb Mark-out

Inside Level Mark-out

Left click, release and drag to measure at scale inside diagram.

Spiral stair profile diagram with full dimensions

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Spiral Staircase Handrail True Radius Calculator Enter actual rise of handrail for entered angle of rotation.

Flat Radius to Handrail Angle of Rotation Total Height for Rotation

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Example of Projects Completed

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