Green Wood Shrinkage Calculator

Expected movement from green to dry for turned pieces.

Inputs

Green diameter (in)

Green depth (in)

Green wall thickness (in)

Species preset (0=custom)

Tangential shrinkage (%)

Radial shrinkage (%)

Green MC (%)

Target dry MC (%)

Tab to move between fields

Results

Dry short axis (in)

9.41

Dry long axis (in)

9.71

Ovality (in)0.29

Dry depth (in)3.88

Thinnest wall (in)0.47

Thickest wall (in)0.49

Rough-turn wall (in)1

How to Use This Calculator

Enter Green diameter (in), Green depth (in), and Green wall thickness (in).
Set Species preset (0=custom), Tangential shrinkage (%), and Radial shrinkage (%).
Adjust Green MC (%), Target dry MC (%) as needed.
Review Dry short axis (in) and Dry long axis (in).
Use Ovality (in) and Dry depth (in) to inform your decision.

How the result changes with Green diameter (in)

Green diameter (in)	Dry short axis (in)	Dry long axis (in)
4.05	3.81	3.93
13	12.24	12.62
24	22.59	23.3
32	30.12	31.06

What each input means

Green diameter (in): Diameter of the piece as turned green.
Green depth (in): Depth of the turned piece while green.
Green wall thickness (in): Wall thickness as rough-turned.
Species preset (0=custom): 0=Custom, 1=Cherry, 2=Maple, 3=Walnut, 4=Oak, 5=Birch.
Tangential shrinkage (%): Total tangential shrinkage (green to oven-dry). Used when species=0.
Radial shrinkage (%): Total radial shrinkage (green to oven-dry). Used when species=0.
Green MC (%): Moisture content of the green wood (typically 40-100%).
Target dry MC (%): Target equilibrium moisture content (6-10% for indoors).

What each result means

Dry short axis (in): Shortest diameter after drying (tangential direction).
Dry long axis (in): Longest diameter after drying (radial direction).
Ovality (in): Difference between long and short axes — how 'out of round' it will be.
Dry depth (in): Expected depth after drying.
Thinnest wall (in): Wall thickness at thinnest point after drying.
Thickest wall (in): Wall thickness at thickest point after drying.
Rough-turn wall (in): Recommended rough-turn wall thickness to allow for re-turning after drying.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Green diameter (in) = 10, Green depth (in) = 4, Green wall thickness (in) = 0.5, Species preset (0=custom) = 0 = 8 input(s) provided
Calculate Dry short axis
Dry short axis = greenDiameter * (1 - tangentialShrink)
9.413 = 9.413
Calculate Dry long axis
Dry long axis = greenDiameter * (1 - radialShrink)
9.707 = 9.707
Calculate Ovality
Ovality = dryLongAxis - dryShortAxis
0.293 = 0.293
Calculate Dry depth
Dry depth = greenDepth * (1 - radialShrink)
3.883 = 3.883

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