|Formed milling cutters are used to accurately duplicate the
contour of a required surface. The woodruff keyseat cutter (Figure
1) is a form cutter that duplicates the shape of a woodruff Key
Figure 1. Woodruff keyseat Cutter
|Woodruff keys are used when keying or mating parts. Woodruff
keyseats can be cut quicker than a straight keyseat. Woodruff keys
are semicircular in shape and can be purchased in standard sizes.
Figure 2. Woodruff Key.
Woodruff keyseat cutters come in a straight tooth or a staggered tooth
configuration. The shank is undercut next to the cutter to allow for
clearance during cutting operations. Woodruff cutters over 2 inches in
diameter are mounted on an arbor.
The size of the cutter is stamped on the shank. The last two digits of
the number indicate the nominal diameter in eighths of an inch. The digit
or digits preceding the last two digits indicate the nominal width of the
cutter in thirty-seconds of an inch. Thus a 608 cutter like the one in
Figure 1 above would be 8/8 or one-inch in diameter by 6/32 or
To cut a woodruff keyseat:
- Tram or align the head of the vertical milling machine.
- Layout the position of the keyseat.
- Set the shaft in a vise or on v-blocks and level the shaft
parallel with the table.
- Mount the keyseat cutter in a positive lock style of holder.
- Start the spindle at the proper RPM for a form cutter and check
the cutter rotation. Touch the bottom of the cutter to the top of
the work piece using a piece of paper. Set the vertical graduated
feed collar to the paper thickness.
- Move the work clear of the cutter. Raise the table half the
diameter of the work (where you touched off) plus half the thickness
of the cutter. Lock the knee of the milling machine.
- Touch off the cutter on the end of the shaft and find the center
of the slot location on the shaft using the graduated dial of the
milling machine. Lock the X axis traverse direction of the milling
- Touch the revolving cutter to the work using a piece of paper as a
buffer. Set the cross feed graduated dial to the paper thickness.
Using the Machinery’s Handbook calculate the depth of the keyseat.
Cut the keyseat to depth.