CUTTING TOOLS 23 
The iron and cap were held in position by a wooden 
wedge, which was driven in by a light blow of the 
hammer. The workman removed the iron and wedge 
by turning the plane upside down and striking the 
forward part a light downward blow on the bench, 
while the thickness of the shaving was increased by 
a light tap on the plane iron. 
One of the chief objections to the wooden plane was 
its liability to wear and warp, so that it became neces- 
sary to straighten, or joint, the face. No such diffi- 
culty is encountered in the d 
iron-bodied plane. ‘ SF ae { 
15. The Chisel. The chisel , 
is one of the simplest forms © torre | 
of cutting tools. The size of ; 
the angle a depends on the Fie. 29. Cutting Angle of Chisel 
kind of material to be cut. 
A chisel for cutting wood must be sharpened to an 
angle of from 30 to 35 degrees. 
By careless sharpening an extra bevel is sometimes 
formed, as shown at b. 
The cutting angle is then no sharper than if the 
chisel were shaped like that shown by dotted lines, 
and care must always be taken when sharpening to 
keep the line cd straight, so that angle a will be the 
real cutting angle. 
