CUTTING TOOLS 19 
Screw s lowers or raises the plane iron so that we 
may take a thin or thick shaving, and lever / straightens 
the iron, which is liable to project more on one side 
than on the other, and will then take a shaving thicker 
on one side than on the other. 
Before using the plane always examine it carefully. 
Invert the tool, holding it toward the light with the 
toe toward you, and glance along the bottom. If the 
iron projects, observe whether it is even, and if not, 
move the lever until it is. For a thin shaving the cut- 
ting edge should appear as a black line of uniform 
thickness. For a heavy shaving turn the brass screw 
until the iron projects slightly. 
In using the plane avoid a stooping position. Stand 
with the right side to the bench and with the shoulders 
thrown back. Let the pressure of the left hand be 
greater at the beginning and that of 
the right hand at the end of the stroke. 
The tool should rest perfectly flat on b 
the wood from start to finish. 
10. The Jack Plane. The ordinary 4,, 95 tons of 
plane iron has a straight edge, as shown —Smooth and Jack 
at a, Fig. 23, but when a large quantity oor 
of wood is to be removed the iron is sharpened in 
the shape shown at b. This curved iron will cut out 
the wood in hollows, leaving ridges between, and it 
