BULLETIN 527, U. S. DEPARTMENT OF AGRICULTURE. 
length of the board. As the square forms a right angle, the short side 
will then be at right angles to the sides of the board; consequently, 
a line drawn on the board along this short 
side will be at right angles to the side of 
the board. The try square is used for 
squaring up boards, as shown in figure 7, 
and also for testing surfaces and testing 
angles. Figures 15 and 16, pages 6 and 7, 
show these operations. 
The hammer has two uses — to drive nails, 
and to pull nails. When driving nails, grasp 
the handle near the end farthest from the 
head; you 
can strike 
a more ef- 
FlG 
-Squaring up a board with 
a try square. 
Off 9 /ffO/V 
fective blow than if you grasp it 
near the other end. When pulling 
nails, the hammer acts as a lever; 
it is surprising how much puL 
ling force is exerted on the nail. 
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rfPJUSTMENT 
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Fig. 9.— Parts of a plane. 
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Fig. 8.— Plane iron, plane-iron screw, and cap 
iron. 
The plane is used to smooth 
surfaces. The jack plane is 
the one most commonly used. 
The plane iron is the cutting 
part of the tool. Figure 8 
shows the plane iron, the 
plane-iron screw, and the 
cap iron, and figure 9 shows 
a cross section of a plane 
with the different parts 
clearly indicated. With a 
plane before you, examhie all these parts. 
When a plane is properly adjusted the 
plane iron projects the same distance from 
each side of the throat. The adjustment is 
tested by sighting, as shown hi figure 10, 
and by feeling with the fingers to see that 
the edge projects equally on each side. 
The marking gauge is used to gauge, or 
mark, a line parallel to one edge of a 
board. To set the gauge, hold it point 
side up hi the left hand, and with the rule 
in the right hand place the end of the rule 
against the gauge block and see that the 
measurement desired on the rule is at the point of the gauge, as shown 
in figure 11. Tighten the set screw, and the tool is ready for use. 
Fig. 10. — Sighting to adjust a 
plane. 
