The Creative Homebuilder

Gear-leg drill jig.


One of the most challenging moments in some builds comes when the steel gear legs must be drilled for substantial-size motor-mount bolts. To ensure proper hole alignment, the Creative Homebuilder made a gear-leg drill jig in the 1980s to use on his RV-4 build, later on his Rocket, and frequently loans it out to other builders. The welded-metal jig includes two rounded U-bolts that allow clamping the jig to the appropriate gear-leg tube. Welded at the end of the jig is a hollow cylinder oriented normal to the tube at the site where the hole must be drilled. There is a set screw on the side. The cylinder accepts progressively sized drill bushings to slide in and guide the drill, maintaining hole alignment while enlarging the hole.

The drill jig is clamped to the gear-leg tube with U-bolts. Note that the cylinder that holds the drill bushing is perpendicular to the tube at the site where the hole must be drilled.

One drill bushing is placed in the cylinder that is welded to the drill jig, and four additional bushings hang on a piece of safety wire, ready for use as the hole is progressively enlarged.

The advent of the quickbuild option for many kits minimizes the need for the tool compared to the past, but it still proves handy for builders of older kits, like the RV-3 and RV-4.


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