For a basic standoff, a single post Lego brick works fine. Depending on the application, bricks with any number of posts can be used. The following instructions are for a single post brick.
Note: These instructions are for use with 3 mm metric mounting screws. If you wish to use ANSI screws, use 4-40 and a #31 or #32 drill for the holes in the bricks. A 1/8 in (0.125 in) drill works well for the clearance holes in the mounting base.
(1) Hold the brick with a pair of pliers and drill a 3 mm hole through the center of the Lego snap post. This works best using a hand drill and going through the underside of the brick, where a preexisting hole left from the molding process leaves a small blind hole that is perfect for guiding the drill through the center of the snap post (Figure 1).
(2) Hold the brick next to the circuit board to gauge how thick the snap post must be. It needs to be slightly shorter than the width of the circuit board.
(3) Rub the post against a piece of sandpaper (180-220 grit works fine) to remove material until the desired post thickness is achieved (Figure 2).
Note: Rotate the brick around as you sand to try and get the post height to be the same all around.
The standoff is ready to use.