A quick-change (QC) chuck on an air drill allows quicker and more secure bit changes, but only a limited selection of drill bits and tools are commercially available with the dimples that ensure a secure fit in the chuck. However, a quick shopping trip to the fly market to buy a variety of drill bits with enlarged shanks, a piece of 5/8-inch hex shafting, some standard shop tools, and some simple skills allow our Creative Homebuilder to make any specialty size drill he might need. Mostly, the sizes he creates are used for pilot holes for threading or clearance holes for insertion of various screw sizes (#4, 6, 8, etc.).
The project begins by making a drill jig. Take the 5/8-inch hex shafting and bore an approximately .302-inch diameter hole lengthwise to accommodate the enlarged drill shaft. Then drill a threaded hole to accommodate an Allen-head screw in one face for retaining the blank while drilling the QC retention holes. Next, drill #34 pilot holes into each face.
Drill jig for the modified QC shanks (top) and examples of drilled QC retention dimples.
To make your own QC drill bits, place the blank drill bit in the drill jig, tighten the Allen screw, and drill dimples into all six sides of the drill bit shank.
Modified QC tools: 6-inch drill extension, countersink cage, Unibit, Cogsdill Burraway deburring tool.
This technique can be used for almost any normally chucked tool. For example, the Creative Homebuilder added a QC shank to a Cogsdill Burraway deburring tool. This tool has a spring-loaded cutting blade that removes burrs from both the front and back of holes at the same time. Simply engage the front edge of the blade on the front face, push through the skin enough to clear the blade on the backside, and then pull the blade back through, deburring while doing so. The tool is very handy in areas where access to the back of the skin is restricted.
Quick-change retention dimples can also be added to Unibits, countersink cages, drill extensions, and more. Having an extensive set of QC drill accessories makes it very convenient to quickly couple tools to the drill. Over the course of a large project, it can save a significant amount of time.