PLAIN MILLING CUTTERS
Arbor-mounting cutters are cylindrical in form and provided with cutting edges of their outer cylindrical
surfaces. There are no cutting edges on either side of a plain milling cutter. Plain milling cutters are
used normally for machining flat surfaces.
Arbor-mounting cutters with small widths, ranging from a few thousandths up to 3/16 inch, are called
slitting saws. They are used for cutting off and narrow slotting operations. Most slitting saws are similar
to plain milling cutters as they have cutting edges only on their outer cylindrical surfaces. These slitting
saws are ground slightly concave on their sides to provide side clearance so that their sides will not rub.
Some slitting saws, especially those with greater widths, nearer 3/16 inch, are used as side milling
cutters.
FLY CUTTERS
A fly cutter consists of one or more single-point tool bits mounted in a bar of some type that can be
attached to the spindle of the milling machine. Its principle in operation is quite like that of a boring tool.
Setscrews are used to hold the tool bit in place; this type of tool is used for special applications.