FDM
WOOD EXPLORER
fdmonline.com
Gene Wengert
wooddoc@uwalumni.com
Knotty and narrow; used for
furniture, cabinets:
Jack pine
Jack pine (Pinus banksiana) is found
in northeastern North America,
ranging from Nova Scotia to
northern Ontario, south to Michigan
and east to northern New York. Other
common names include blackjack pine
and pin de Banks.
Jack pine is a rather small tree,
reaching heights of 65 feet and seldom
much more than 14 inches in diameter. As a result, lumber will be quite
narrow.
Lumber from jack pine is generally
knotty. In lumber markets, jack pine is
sometimes included along with other
pines that it grows with, including red
pine.
Jack pine is used for pulpwood and
pallets. It has very dramatic red knots
that certainly make it worthwhile to
consider this wood for knotty furniture
or cabinets.
It’s also relatively stable when the
RH changes. Jack pine is moderately
light in weight and moderately low in
strength.
Some people report skin and nasal
allergies from contact with the wood,
especially the fine dust. This is typical
of many of the pines. ●
Processing suggestions and characteristics
Density. The density of jack pine is about 38 pounds per cubic foot
at 10 percent MC. This means that a dried piece of lumber 1 inch by 6
inches by 10 feet (actual size 3/4 inch by 5-1/2 inches by 10 feet) will
weigh 11 pounds. This is more than 20 percent heavier than eastern
white pine, but is close to red pine.
stiffness (MOE) is 1. 35 million psi; and the hardness is 570 pounds.
Corresponding eastern white pine values are 8600 psi, 1. 24 million psi
and 380 pounds. In other words, it’s considerably harder than E WP.
One area of concern is that jack pine is liable to split when nailed
near the end of a piece. Pre-drilling holes will eliminate this tendency.
Drying. Drying is easy, but warp must be controlled using good drying
practices and even weights on the tops of piles. Drying temperatures
should exceed 160 F to set the pitch and thereby avoid resin exudation.
Gluing and machining. Gluing is fairly easy. Resin exudations will
interfere with gluing if drying is not done hot enough.
Machining is moderately good. Certainly sharp tools are suggested. Avoid
drying under 9 percent MC at all costs, as drier wood machines poorly.
Strength. The strength (MOR) of jack pine is 9900 psi; the
Stability. Jack pine is a little more stable than average, requiring a 5
percent MC change or greater for a 1 percent size change in the width of
flatsawn lumber, and 8 percent MC change in quartersawn stock.
Color and grain. The sapwood of jack pine is nearly white, while
the heartwood is light brown to orange. The sapwood may make up
one-half or more of the volume of a tree, so sapwood lumber (with red
knots) is common, as well as is mixed sap and heart pieces.
The wood has a rather coarse texture and is somewhat resinous if
not dried properly.
