North American Walnut Also Often Called Black Walnut
The most common Walnut wood found in Eastern North America is also known as Black Walnut. It is a naturally dark colored grain.
Its scientific name is Juglans Nigra and typically has a straight grain with a medium wood texture. Walnut has a natural medium luster making it great for finishing and polishing.
Walnut is popular to be used in furniture making, cabinetry, and wood art.
Structural Properties Of Walnut Wood
The estimated specific gravity of Walnut wood can range from .51 to .70 depending upon the selection and process used.
Its density is 630 kg/m3 or also rated between 38 to 43 lb/ft3. This places Walnut behind Hard Maple, Red Oak, and Ash. Though it has more density than Teak, Cherry, and Soft Maple.
Janka hardness is rated at 1,010 lbf or 4,490 N.
Walnut crushing strength is rated at 7,580 lbf/in2 or 52.3 MPa. This places Walnut behind Teak and Hard Maple but in front of White Oak and American Beach.
The average dried weight of Walnut is 40 lbs/ft3 or 460 kg/m3
Radial shrinkage is 5.5% and Tangential is at 7.5%. Volumetric shrinkage is 13% and a T/R ratio of 1.4
Characteristics Of Walnut Wood
Walnut is moderately durable in rot resistance. It is susceptible to insects and does not have a natural defense to these attacks.
The color of the wood grain can vary from light or pale brown to dark brown. At times you can find strong darker grain lines making the wood exceptionally beautiful.
While the wood grain is more commonly straight, the dark grain lines can sometimes curl giving added beauty.
The end grain is an open grain wood having Semi-ring porous or Semi-diffuse porous. With Walnut the pores are large in the earlywood and small in the latewood.
This allows for the growth rings to be distinct within the end grain and often with color variation within the grain lines.
Cutting And Carving With Walnut Wood Grain
If you use a hand plane to work Walnut, the straight grain will rarely give any issues or trouble. The mechanical plane can at times yield tear out.
Surfacing can also produce tear out especially within irregular grains. Speed and feed rates play a critical role in preventing burning from a surfacing bit.
The grain can show burn lines if these speeds are too slow or aggressive in the surfacing cut. It is best to remove smaller portions of material per pass at higher feeding speeds.
Walnut is easy to sand to gain a smooth surface and its end grain will finish beautifully. Sanding to remove lines caused by surfacing bits can be troublesome if an improper process was used.
It is best to approach these cuts in smaller or more shallow cuts. Mechanical cuts from tools like vbits do well yet again be aware of potential burning from the bits feed and speed.
Sustainability Of Walnut Wood
Most of the Walnut we have from North America today comes from tree farms. While the species is not on the red list of threatened species it is not as commonly found in the wild as other species.
Walnut is considered a premium hardwood and is highly sought after by woodworkers. With this demand the prices for the species are higher than other domestic wood prices.
Benefits Of Walnut Hardwood
Walnut offers a great balance in shock resistance, durability, and also the ease of carving the wood. Its wood strength gives value to its uses in furniture making or being used for accessories like gun stocks or knife handles.
Within wood art we find Walnut giving a unique beauty that few other North American hardwoods can offer. It allows for a natural contrast of color and grain structure to compliment art pieces.
While Walnut would be considered a more advanced wood for carving it is forgiving. Beginners can carve Walnut to practice techniques expecting to achieve consistent results.
It is a great wood for transitioning from beginner wood carving to more advanced techniques.
In terms of machining mechanically it does take more care to preserve the state of the wood. Here it can be less forgiving for errors in a manufacturing process.