Tc 9-524 fundamentals of machine tools

Milling Cutters Used for Milling Keyways
Shaft keyways for Woodruff keys are milled with Woodruff
keyslot milling cutters (Figure 8-35). The Woodruff keyslot
milling cutters are numbered by the same system employed
for identifying Woodruff keys, Thus, a number 204 Woodruff
keyslot cutter has the proper diameter and width for milling a
keyway to fit a number 204 Woodruff key.
Square-end keyways can be cut with a plain milling cutter
or side milling cutter of the proper width for the key
Round-end keyways must be milled with end milling cutters
(Figure 8-37) so that the rounded end or ends of the key may
fit the ends of the keyway. The cutter should be equal in
diameter to the width of the key.
Alignment of Milling Cutters
When milling keyways. the shaft may be supported in the
vise or chuck, mounted between centers. or clamped to the
milling machine table. The cutter must be set centrally with
the axis of the workpiece. This alignment is accomplished by
using one of the following methods:
When using a Woodruff keyslot milling cutter, the shaft
should be positioned so that the side of the cutter is tangential
to the circumference of the shaft. This is done by moving the
shaft transversely to a point that permits the workpiece to
touch the cutter side teeth. At this point the graduated dial on
the cross feed is locked and the milling machine table is
lowered. Then, using the cross feed graduated dial as a guide,
the shaft is moved transversely a distance equal to the radius
of the shaft plus 1/2 the width of the cutter.
End mills may be aligned centrally by first causing the
workpiece to contact the periphery of the cutter, then
proceeding as in the paragraph above.
Milling Woodruff Key Slot
The milling of a Woodruff keyslot is relatively simple since
the proper sized cutter has the same diameter and thickness
as the key. With the milling cutter located over the position in
which the keyway is to be cut, the workpiece should be moved
up into the cutter until you obtain the desired keyseat depth.
Refer to Table 8-4 in Appendix A for correct depth of keyslot
cut for standard Woodruff key sizes. The work may be held in
a vise. chuck. between centers. or clamped to the milling
machine table. Depending on its size, the cutter is held in an
arbor or in a spring collet or drill chuck that has been
mounted in the spindle of the milling machine.