Is walnut hard enough for furniture and flooring?

Walnut has a Janka side-hardness of 1010 lbf (the USDA Forest Products Laboratory reference value at 12% moisture content), placing it in the medium range for domestic hardwoods. It is a long-standing choice for furniture, cabinetry, interior paneling, and turned objects.

Can walnut be used outdoors?

Its heartwood is very durable against decay, but insect resistance is only moderate, so it is best suited to interior and protected exterior service rather than fully exposed outdoor use.

How does walnut work with hand and machine tools, and where does Raw Heartwood's walnut come from?

Walnut works clean under both hand and machine tools, holds its dimension, and glues, stains, and finishes well, though figured stock near crotches and stumps wants sharp tools and a measured hand to avoid tearout. Raw Heartwood mills its walnut from urban-salvaged logs in the Chicago area and kiln-dries the lumber to 6-8% moisture content.

DomesticJuglans nigra

Walnut

T/R ratio of 1.4. The premier domestic furniture wood.

Walnut (Juglans nigra) is a domestic hardwood from the eastern and central United States with a Janka hardness of 1010 lbf. Its heartwood runs pale brown to dark chocolate, sometimes with purple or red streaks, and it holds its shape unusually well for its weight class.

Category: Domestic
Janka: 1,010 lbf
Botanical: Juglans nigra
Shipped at: 6–8% MC

Juglans nigra Black Walnut · Black Walnut · Eastern and central United States

Eastern and central United States.

T/R ratio of 1. Heartwood pale brown to dark chocolate.

Detail of Walnut grain — figured wood texture, photographed at Raw Heartwood — A close read on the grain. Detail of this specimen

What you see.

Heartwood pale brown to dark chocolate. Sometimes purple, sometimes red streaks. Sapwood is pale yellowish white, sharp contrast — though most lumber comes steamed, which pulls the color into the sap and evens it out. With time and light the heart lightens toward golden brown.

Heartwood color detail of Walnut (Juglans nigra)

Heartwood, this specimen

How the grain runs.

Mostly straight. Wavy and curly stock turns up near crotches and stumps — that is where the figured veneer comes from. Medium texture, good luster.

Closer in

On the bench.

Heartwood is very durable for decay. Insect resistance is moderate. Interior and protected exterior service is fine. Works clean under hand and machine. Holds dimension. Glues, stains, finishes well. Sharp tools and a measured hand on figured stock or it tears. Mild at the cut. Reported to irritate skin, eyes, and lungs. Juglone — concentrated in bark and husks, less in the wood — is the allelopathic compound, toxic to plants and to horses. Some workers react.

The numbers, looked at directly.

Janka Hardness

0lbf

4,490 N. Side-hardness — force to embed a half-inch steel ball halfway into the wood.

Average Dried Weight

0lbs/ft³

610 kg/m³. At 12% MC.

Specific Gravity

0.51/ 0.55 at 12% MC

Basic over green volume; second number at 12% moisture content.

Hardness, in context

A side-hardness measurement. Higher number, harder wood.

Shrinkage — radial / tangential / volumetric

5.5%radial

7.8%tangential

12.8%volumetric

On sourcing

Where this wood comes from matters.

Not on CITES. IUCN Least Concern. Managed across its range. Veneer logs cost what they cost; supply has tightened.

What it's for.

Furniture
Cabinetry
Gunstocks
Interior paneling
Veneer
Turned objects
Instrument bodies

Worth knowing.

T/R ratio of 1.4 — radial and tangential shrinkage are unusually close. That is why walnut holds its shape better than nearly anything in its weight class. Most commercial walnut is steamed during drying. The unsteamed alternative — sometimes specified by studio makers — keeps the original two-tone contrast.

Sources & references.

Wood Handbook — Wood as an Engineering Material (FPL-GTR-282) — USDA Forest Service, Forest Products Laboratory (2021)
Black Walnut (Juglans nigra) — FPL Tech Sheet — USDA Forest Service, Forest Products Laboratory
Silvics of North America: Juglans nigra L. — Black Walnut — Williams, Robert D. (USDA Forest Service) (1990)
Juglans nigra — IUCN Red List of Threatened Species — Stritch, L.; Barstow, M.; Rivers, M.; Carrero, C. (2017)
Juglans nigra — Wikipedia contributors
Black Walnut (Juglans nigra) — The Wood Database
American Black Walnut — Species Guide — American Hardwood Export Council (AHEC)
The Walnut Tree: Allelopathic Effects and Tolerant Plants (Publication 430-021) — Appleton, Bonnie; French, Susan; Koci, Joel; Harris, Roger (Virginia Cooperative Extension)

Common questions.

Is walnut hard enough for furniture and flooring?: Walnut has a Janka side-hardness of 1010 lbf (the USDA Forest Products Laboratory reference value at 12% moisture content), placing it in the medium range for domestic hardwoods. It is a long-standing choice for furniture, cabinetry, interior paneling, and turned objects.
Can walnut be used outdoors?: Its heartwood is very durable against decay, but insect resistance is only moderate, so it is best suited to interior and protected exterior service rather than fully exposed outdoor use.
How does walnut work with hand and machine tools, and where does Raw Heartwood's walnut come from?: Walnut works clean under both hand and machine tools, holds its dimension, and glues, stains, and finishes well, though figured stock near crotches and stumps wants sharp tools and a measured hand to avoid tearout. Raw Heartwood mills its walnut from urban-salvaged logs in the Chicago area and kiln-dries the lumber to 6-8% moisture content.

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