Feed

It is the distance a drill moves, parallel to its axis, into the work in each revolution of the spindle. It is expressed in mm per revolution. If the total distance moved by the drill into the work, parallel to its axis, in one minute is considered, it can be expressed as feed in mm per minute. Now, if N be the No. of revolutions made per minute by the drill, then:

Feed in mm/min = feed in mm/rev × N

The following factors govern the amount of feed to be provided :

1. Workpiece and drill material

2. Depth of drilling

3. Range of available feeds

4. Rigidity of the machine

5. Degree of surface finish required

6. Horse power of the motor

7. Drill size and speed