I have a hard time countersinking the mounting screws when using aluminum T-tracks in jigs.


I like to use aluminum T-track in jigs and projects. However, I have a hard time countersinking the mounting screws. If I drill the countersink deep enough to seat the screwhead flush, do I risk enlarging the holes too much by countersinking into the stock?
—Rick Shields, Portland, Ore.


Don't worry about overenlarging the hole in your aluminum T-track, Rick. The metal-to-metal contact of the angled screwhead and the angled countersink bottom holds the track in place, not the shaft of the screw within the pilot hole.

To install a T-track, first clamp the track in place, making sure the top of the track is flush with the jig's surface. At the drill press, drill pilot holes through the track and into the jig; then countersink the screw holes with the track still clamped in place. We recommend single-flute countersinks (no. 06J50.20, Lee Valley Tools, 800-871-8158 or leevalley.com). These allow you to accurately center a smooth cut. Drill until the upper diameter of the countersink matches the diameter of the screwhead, as shown below. That may mean the tip of the countersink bit cuts through the track and into the jig, but this shouldn't create a problem; there will still be plenty of material for the screwhead to grab. Just be certain you center the countersink over the pilot hole.