Civil Engineering Reference
In-Depth Information
Fig. 7.3 Take the ends of a slot to size before removing the middle.
Machining a keyway
It is easy enough to machine a keyway, but a little care is needed. Firstly, the
slot drill should be in good condition. If the slot drill has previously been used
make sure it is not part worn on the lower sides of the cutting edge. This could
lead to a stepped keyway and cause difficulty in fitting the key. If in doubt, use
a new slot drill for each different depth of keyway required.
Slot drills (the two-flute and the FC3 throwaway three-flute ones) are de-
signed to cut about a
1
⁄
2
thou small, which is ideal for a keyway. The keyway
should be cut to depth in one pass and in one direction, using a very slow or
hand feed.
