Page 18 of Advanced Drilling Equipment by Cooper Power Tools

introduction in-line positive feed tools how positive feed drills operate our in-line positive feed drills use two interconnected mechanisms one to control the spindle rotation and one that controls the advancement or feed rate of the spindle the tool spindle is driven rotationally through an internal spline by a drive shaft connected directly to the motor through gearing when the motor is tool nose our positive feed drill motors are available in piggyback in-line and right angle configurations please see the following section for right angle tools in general positive feed drills are used for the large holes and heavy structures in the aircraft such as the spars ribs landing gear wings and fuselage a positive feed drill will advance the cutter at a fixed distance in relation to the revolution of the cutter this is true regardless of the application since the cutter advances a precise distance with each revolution the cutter 2 does not rotate without cutting this reduces heat and deformation resulting in less chance of the material work hardening another key benefit delivered by these drills is that surge at breakthrough is 6 virtually eliminated because there is no surge of the cutter on the exit side burrs are reduced or eliminated these drills range in stroke from 1.25 to 7.50 they may be used on all types 5 of material and can drill holes from .125 to 2.50 in diameter in aluminum our in-line drills are available in either a straight or piggy back design and 3 both are advantageous in tight operating circumstances in which a right angle tool might have clearance concerns 4 many of the accessories for our 1 in-line and right angle tools are interchangeable such as chucks nose pieces motors and gears 3-jaw chuck forward stroke adjustment return spring on/off throttle feed engagement collar air motor half nuts lead screw rear stroke adjustment collar cross-feed gearing and overload clutch for positive feed 1-2

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