CutMath

Black Oak

Quercus velutina · hardwood · Eastern North America · high movement

Field data
  • Janka hardness 1,210 lbfred oak ≈ 1,290 lbf
  • Density ≈ 43 lb/ft³specific gravity 0.61 at 12% MC
  • Shrinkage — tangential 11.1%flatsawn width, green → ovendry
  • Shrinkage — radial 4.4%quartersawn width
  • T/R ratio 2.5 : 1higher = more cupping in flatsawn stock

Shop notes A red-oak-group species usually sold in the red oak mix. High tangential shrinkage — pick quartersawn boards for anything wide.

Seasonal movement at a glance

Width change for black oak across a typical indoor year — 6% moisture content in the heated winter to 12% in a humid summer:

Board widthFlatsawnQuartersawn
6″ 5/32″ (0.143″) 1/16″ (0.057″)
12″ 9/32″ (0.285″) 1/8″ (0.113″)
24″ 9/16″ (0.571″) 7/32″ (0.226″)
36″ 27/32″ (0.856″) 11/32″ (0.339″)

Run your own numbers

Different width, different climate swing — the calculator below is preset to black oak:

Board & conditions
Grain
Conditions given as

Typical swings:

Movement estimate
    Estimate Figures use species-average shrinkage from the USDA Wood Handbook and the standard shop movement formula. Individual boards vary — leave margin, especially with flatsawn stock.

    Black Oak questions

    How much does black oak move with the seasons?

    A 12″-wide flatsawn black oak board moves about 9/32″ across a typical indoor swing from 6% to 12% moisture content; quartersawn, about 1/8″. Its tangential shrinkage is 11.1% and radial 4.4% (green to ovendry) — a high-movement wood.

    How hard is black oak?

    Black Oak rates about 1,210 lbf on the Janka scale — in red oak’s hardness neighborhood (red oak is roughly 1,290 lbf). Density runs about 43 lb/ft³ at indoor moisture levels.

    Is black oak good for wide panels and tabletops?

    Carefully. Its tangential-to-radial ratio of 2.5:1 makes flatsawn boards prone to cupping — choose quartersawn stock for wide glue-ups, alternate growth rings, and fasten tops so they can slide.

    Similar species

    Green Ash · Black Maple · Oregon Ash · Yellow Birch · Iroko · Northern Red Oak

    Shrinkage, specific gravity, and hardness from the Wood Handbook, FPL-GTR-282 (2021 edition), USDA Forest Products Laboratory (public domain). Values are species averages — individual boards vary with growth conditions and how they were dried.