Species Specs: Walnut, Black American

Image courtesy of courtesy the Missouri Department of Conservation.

Juglans Nigra

ORIGIN:
A deciduous tree found primarily in the eastern U.S. Grows from Vermont to the Great Plains, south to Louisiana and Texas. The majority is grown in the central states. Readily available.

USES:
American black walnut is a highly sought-after species commonly used in flooring, cabinet making, furniture, gunstocks, musical instruments, boatbuilding, architectural woodwork, handles, and decorative veneers. The nuts from the tree are edible. Walnuts also produce a natural dye, available in the popular walnut brown color.

COLOR:
The heartwood ranges from light greyish brown to dark chocolate brown or even purplish black. The sapwood is nearly white to yellowish gray or tan. The color difference between the heartwood and sapwood is drastic unless steamed during the manufacturing process.

GRAIN:
The grain is normally straight and open. It can also be irregular, curly, or wavy. Burls, crotches, and knots add the unique characteristics for which walnut is often known. Walnut is semi-ring porous.

VARIATIONS WITHIN SPECIES AND GRADES:
Great variety of color and figure within the species, as well as variation in color among boards, especially in lower grades and from material that has not been steamed before kiln-drying.

HARDNESS (JANKA):
1010

DIMENSIONAL STABILITY:
Average – American black walnut has a dimensional stability factor of 5.5 percent (radial) and 7.8 percent (tangential), meaning this species may shrink/swell up to 7.8 percent of its given width, depending on how it’s cut, when going from green (30 percent MC) to oven-dried.

DIMENSIONAL CHANGE COEFFICIENT:
.00190 (radial), .00274 (tangential)

SPECIFIC GRAVITY:
.55

NAILING:
No known issues, but can sometimes have a tendency to split the tongues dependent on fastener placement and grain orientation.

SANDING:
A softer species that sands satisfactorily. It can be difficult to sand because of the density, which can make sander marks show more than on some woods. Some people are very allergic to walnut dust; respirators are highly recommended when sanding. Normally required to bring sanding sequence to a higher grit to minimize visible scratches. When sanding walnut that has been installed along with harder, denser species, it is important to sand on diagonal and/or use a hard plate or multi-disc sanders to minimize dish out. Staining walnut can minimize long-term effects of the inherent lightening properties to which walnut is prone.

Sources:
Wood Handbook (Wood as an Engineering Material), USDA Forest Products Laboratory | WOOD!; Copyright © 2016, Eric Meier | Wood Identification and Use; Copyright © 2006, Terry Porter | Missouri Department of Conservation

 

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