Take the guesswork out of mounting drawer slides
Mounting a drawer box so its face aligns with the cabinet frame can be as frustrating as catching a greased pig. When you're installing full-extension drawer slides, as I like to do, there's even less room for error. My solution was to build a pair of L-shaped drawer supports, as shown, that clamp to the cabinet front and fully support the drawer box while leaving my hands free. Use the dimensions shown in the illustration to build your supports, remembering to make both a left and right version. The 12" spacer is long enough to extend past the support and rest firmly on the cabinet's face frame for alignment. The spacer on top of the support holds the drawer box the necessary 1⁄4 " above the face frame rail. With the box securely supported and accurately spaced, it's simply a matter of extending the drawer slide out until it's flush with the box's front and screwing it into place.
—Paul Bianchina, Bend, Ore.