Often with lighter cuts and especially with hand feeding, a key is not used. If a milling cutter driven
without a key slips when power feed is being used, the amount of material to be removed by the next
cutter tooth may be increased. This may cause either more slippage or possible breakage.
PLAIN MILLING CUTTERS
Plain milling cutters are cylindrical with teeth on the periphery only. The periphery of a milling cutter is the
imaginary cylindrical surface enveloping the outer ends of the peripheral teeth and determining the
diameter of the cutter. These cutters are used primarily for milling flat surfaces. They can be combined
with cutters of other types to produce surfaces with various forms. The teeth may be either straight or
helical, depending upon the width of the cutter. Plain milling cutters with helix angles of 45° to 60 ° and
higher are called helical cutters.
ANGULAR MILLING CUTTERS
Angular milling cutters are used for operations such as: cutting V-grooves, notches, dovetails, flutes on
milling cutters, and reamer teeth. Single-angle cutters have one angular surface while double-angle
cutters are made with V-shaped teeth. These cutters, with equal conical angles on both faces, are made
with an included angle of 45°, 60°, or 90°.