Positive feed, and air feed drills are the two basic drill systems used for repetitive drilling operations. Positive feed drills are typically used to drill holes 3/8" and larger, to minimize the fatigue to the operator. However, Positive feed drills are typically larger and heavier than air feed drills. When drilling holes smaller than 3/8" in materials less than ¾" hick, air feed drills offer the advantages of a smaller, lighter drill that can be used in more confined areas.
The PFO4 series attachment used on a .9 HP UNIVERSAL TOOL air drill from ANDREWS TOOL COMPANY, is used extensively in the aerospace industry. Critical to the overall efficiency of this type of drilling operation is the ability to change the "feed rate" to suit various hole diameters and type of material being drilled. Engineers, accordingly, have developed specific "feed and speed" references for each situation.
With the inclusion of the Deschner Kinechek® hydraulic speed regulator on the Andrews Tool air drill, the feed rate may be easily increased or decreased. This speed regulator saves significant down time by simply turning the built in adjustment knob. In contrast, a traditional positive feed drill motors' feed rate is controlled by a screw mechanism that requires stopping the operation to change the screw adjustment mechanism.
Air feed drills with an easily adjustable speed regulator offer an efficient solution to repetitive small hole drilling operations.