Pilots

The pilot positions the stock strip in relation with the die opening. This is termed as registering the stock in the required position. Usually the stock strip is over fed than the actual pitch length. The maximum over feeding of the strip is about 0.1mm. When the press is tripped the pilot comes down and engages the pre pierced hole, thus dragging the strip back into the registry position.

The accuracy with which the work can be registered depends upon the proper location and the diameter of the pilot.

The following will indicate the pilot diameter;

For an average work, ø of pilot = ø of hole to be piloted-0.05 to 0.1 mm

For close work, ø of pilot = ø of hole to be piloted - 0.03 to 0.05 mm

For accurate work, ø of pilot = ø of hole to be piloted – 0.01 to 0.02 mm

Registering the strip must be complete before the cutting punches come and engage the strip. Therefore the pilots must be longer than the punches. If the pilots are too short, they cannot perform their function. This creates serious consequences ranging from spoiled work to damaged pilots. In any case the piloting length should extend beyond the punch face equal to one sheet thickness.