Theory of Operation - Series 28 Automatic Feed Drills & Tappers

The two basic operating movements incorporated into Dumore Series 28 automatic feed drills & tappers are controlled rotation and traverse. Rotation is supplied via an induction type electric motor transmitted to the cutting tool through a selective timing belt and pulley combination and a precision quill. Rate of rotation (rpm) is determined by the pulley combination selected. Eight different sized pulleys are included with the Series 28 automatic feed drill & tapping unit.
 
When using Dumore Series 28 automatic feed drills & tappers for tapping, the reversing operation of the spindle is accomplished by electrically reversing the motor, using the tapping control panel. Reversing is automatic once the spindle has reached the forward end of the stroke and is simultaneous with the retraction of the spindle. The motor is again reversed at the retracted end of the stroke, ready for the next cycle.
 
Traverse is the advance and retract movement of the rotating cutter and is caused by controlled air pressures. These air pressures are created at the installation air source (air compressor) and transmitted through an airline, filter, and oiler to the automatic feed drill & tapper unit control panel. Dumore Series 28 automatic feed drills & tappers have a built in air regulator.
 
Basic electrical and pneumatic controls are built into Dumore Series 28 automatic feed drills & tappers to simplify automatic operation. The control’s primary purpose is to regulate the amount of pneumatic pressure, how fast the air should move, and when it should act.


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