How a Drill Cuts
Parts of a Twist Drill
Clamping Work for Drilling
Correct clamping technique. Note that clamp is parallel to work. Clamp slippage can be reduced by placing a piece of paper between the work and the clamp.
Incorrect clamping technique. T-bolt is too far from work. This allows the clamp to spring under pressure.
Sharpening a Drill
Hold the point lightly against the rotating wheel and use three motions of the shank: to the left, clockwise rotation, and downward.
Centering Round Stock
To align the hole for drilling through exact center, place the work and Vblock on the drill press table or on a surface plate. Rotate the punch mark until it is upright. Place a steel square on the flat surface with the blade against the round stock as shown above. Measure from the square blade to the punch mark, and rotate the stock until the measurement is the same when taken from both sides of the stock.
A sectional view of a hole that has been drilled and counterbored to receive a socket-head screw.
Counterbores with carbide indexable inserts. The inserts are rotated when a cutting edge becomes dull.