Hickory and pecan

Hickory and pecan

Hickory lumber (Genus: Carya) comes from eight different trees, four species called “true hickory” (shagbark, pignut, shellbark and mockernut) and four species of “pecan hickory” (bitternut, pecan, water hickory and nutmeg hickory).

In the marketplace, you can get any of the eight species when you buy hickory lumber. True hickory is found throughout the eastern United States. However, the range of pecan hickories is limited; bitternut is throughout the eastern United States; pecan is found from Texas to Louisiana, through Missouri and Indiana; water hickory is found in Texas through South Carolina; and nutmeg is found in Texas and Louisiana. Separation of lumber into the two groups is impossible unless chemical or microscopic tests are used. However, many users indicate that they prefer true hickory as they believe it has better color and seems to handle better. Character hickory (with knots, streaks and similar; low grade lumber which keeps costs under control) has also recently become popular for furniture, cabinets and flooring.

Hickory has many uses, including baseball bats (true hickory is preferred), tool handles (excellent shock resistance), drum sticks (true hickory only), furniture (growing in importance) and cabinets.

Processing suggestions and characteristics

Density. The density of true hickories averages about 50 pounds per cubic foot at 8 percent MC. This is heavier than oak. Pecan hickories average about 42 pounds per cubic foot. A dried and planed board foot of lumber will weigh more than three pounds.

Drying. Both hickories are difficult to dry and require close control of drying environments. The wood can check if dried too quickly. Staining if dried too slowly or stored when green is likely, especially a blotchy type gray stain or overall pinking. Shrinkage in drying is around 7 percent.

Final moisture content for hickory should be 6.5 to 7.5 percent. Higher MCs cannot be accepted due to hickory’s high shrinkage; lower MCs result in excessive chipped grain.

Gluing and machining. Hickory is very unforgiving when gluing due to its high density. Surfaces must be flat, smooth and freshly prepared. Clamp carriers are probably best for this wood. True hickory is more difficult to glue than pecan hickory.

Machining of hickory is difficult due to its density. Chipped grain is common if knives are not sharp. Dull knives also result in a rough flatsawn surface where the large vessel cells are located. Correct MC is critical. With proper knives and machines, the surface is excellent in quality, however. Usually, machine tools need to have a larger tool (or sharpness) angle, thereby increasing the amount of metal in the tool.

Stability. Hickory is not too stable when the MC changes. Hickory changes about 1 percent in size for each 3 percent MC change running across the grain parallel to the rings (tangentially), and about 1 percent size change for each 4 percent MC change across the rings (radially).

Strength. The hickories are one of the strongest native softwoods. Bending strength (MOR) averages 19,500 psi for true hickory and 16,000 psi for pecan. Stiffness (MOE) averages 2.0 million psi for true hickory and 1.8 million psi for pecan.

Color and grain. I think that the true hickory group has more uniform and lighter color than the pecan hickory group. Both seem to have nice grain and color character, however, after finishing. If dried correctly, the heartwood is fairly white colored, with tinges of brown and sometimes red. The large pores in hickory present some of the same finishing problems as oak, hackberry and ash.

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