MIL-DTL-6070C
4.5 Tests.
4.5.1 Testing straightness of grain. The slope of the grain requirement in 3.5 shall be determined by
combining the grain direction of two adjacent faces of a square or rectangular piece. When one or more
faces is straight grained, the true slope of the grain is shown on the other face. When there is a slope on
both faces, the true or combined slope is greater than the slope on either face. Slope of grain is shown on
edge-grained faces by summer-wood bands; by the direction in which a free flowing ink or dye spreads;
by the course taken by a narrow strip lifted by a knife point and torn out, or by the Teco or edge slope-
grain Detector. Slope of grain from the edge of the sheet may be readily determined in rotary cut veneer
by tearing the sheet and measuring the slope of the tear.
4.5.2 Mandrel bending tests. The size of the specimen for mandrel bending tests, when required, (see
3.5), shall be one inch across the grain of the veneer and between nine and eleven inches in length. The
ration of the radius of the mandrel to the thickness of the veneer shall be as specified in Table IV. The
specimens shall be cut with the minimum slope of the grain from the edges and shall be oven dry at the
time of the test, the tight side of the veneer shall be outward and the open side against the mandrel. The
specimens shall be bent at the specified radius to a parallel-sided "U" shape without support on the
tension side. Breakage shall consist of fractures extending 1/8 inch or more across the width of the
specimen. Tears along the fiber direction that begin at the edge and extend into the specimen along grain
sloping from the edge shall not be considered breakage. Whether a specimen breaks shall be determined
before removal
from the mandrel. Breakage of more than 20 percent of all the specimens tested shall be considered cause
for rejection of the flitch, crate, or stack.
Table IV. Ratio of radius (R) of mandrel to thickness (T) of different species
for use in mandrel bending tests .
Group of Species
Douglas-fir
Magnolia,
Basswood,
Noble Fir
American Elm,
Soft Maple,
Western Hemlock
Sweetgum,
Yellowpoplar,
Spruce, White
Birch,
Water Tupelo,
Red and Sitka
Alaska and Paper Recan
Sycamore,
Thickness
Port Orford
Black Walnut,
Mahogany,
of
White Cedar
Sugar Maple,
Khaya
Veneer
Pine Ponderosa
Yellow Birch,
Pine, Sugar
Beech
Inches
Ratio R/T
0.011 and 0.020
46
34
47
0.030
46
34
57
0.034 to 0.047
50
40
57
0.060
55
50
67
4.5.3 Specific gravity tests. Specific gravity of veneer shall be determined in accordance with ASTM
D2395. The thickness shall be measured to the nearest 0.001 inch. Specimens may be oven dry at time of
test or the weighings may be made at the prevailing moisture contents providing that the proper
corrections are made to convert to oven-dry weight and volume for comparison with the values in Table I.
If the average specific gravity of the specimens selected is below the minimum specified in Table I,
additional specimens, at least 20 from at least 4 additional sheets of veneer or at least 10 from each end of
each bolt or flitch, shall be cut and the specific gravity determined. If the average specific gravity of all
specimens (original specimens plus additional specimens) is below the minimum specified in Table I, the
veneer from that crate, stack, bolt, or flitch shall be rejected. If the average of all determination is above
the minimum but the average specific gravities of individual sheets are below the minimum specified in
Table I, those individual sheets whose average specific gravity is below the minimum shall be rejected.
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