radial teeth. On some coarse helical tooth cutters the
tooth face is undercut to produce a smoother cutting
straight or helical. When the width is more than
action. Coarse teeth decrease the tendency of the
3/4 inch, the teeth are usually helical. The teeth of a
arbor to spring and give the cutter greater strength.
straight cutter tool are parallel to axis of the cutter.
This causes each tooth to cut along its entire width at
the same time, causing a shock as the tooth starts to
A plain milling cutter has a standard size arbor
cut. Helical teeth eliminate this shock and produce a
hole for mounting on a standard size arbor. The size
free cutting action. A helical tooth begins the cut at
of the cutter is designated by the diameter and width
one end and continues across the work with a smooth
of the cutter, and the diameter of the arbor hole in the
shaving action. Plain milling cutters usually have
Figure 7-23.--Milling cutter terms.