Bowl Segment Calculator

Bowl Segment Calculator for Segmented Woodturning

The Bowl Segment Calculator finds cutting angles and segment dimensions for segmented wood bowl rings. Enter segment count, outer radius, ring thickness, and optional fudge factors for turning allowance. Use the output to cut staves on a miter saw before gluing rings for lathe turning.

Segmented bowl formulas

Cutting angle (miter setting):

$$\alpha = \frac{180°}{n}$$

Outer segment length:

$$L_o = 2 \times \tan\left(\frac{180°}{n}\right) \times (R_o + a_o)$$

Inner segment length:

$$L_i = 2 \times \sin\left(\frac{180°}{n}\right) \times (R_i - a_i)$$

Where $n$ is segment count, $R_o$ is outer radius, $R_i = R_o - T_r$ is inner radius, and $a_o$, $a_i$ are fudge allowances.

Related tools: Angle Cut Calculator and Board Feet Calculator.

Frequently Asked Questions

What is segmented wood turning?

Segmented turning builds a bowl from glued wood staves arranged in rings. Each ring is turned on a lathe after glue-up to form the final profile.

What is a fudge factor?

A fudge factor adds extra material on the inner or outer edge so you can turn away stock without making segments too thin after shaping.

How many segments should I use?

More segments create smoother curves but smaller pieces that are harder to glue. Eight to twelve segments is common for medium bowls.

What miter angle do I set on the saw?

Set the saw to $\alpha = 180° / n$. For 8 segments, that is 22.5°. The calculator shows this value automatically.

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