The 1/4-inch-diameter, 3 1/8-inch-long Top Star Shim Screw has a 3/8-inch-diameter thread around its head. You drill a pilot hole, then — using a special bit made by the company — drive the threaded cylinder and screw into place as a unit. Although the cylinder stays firmly locked in the jamb, the inner screw will turn freely within it, so the installer can drive it in or back it out to adjust the distance between frame and jamb. Since the cylinder sits flush with the surface, you may want to hide it behind a hinge leaf. A six-pack costs $14.
GRK Fasteners, 800/263-0463, grkfasteners.com.
This video was produced by GRK Fasteners. JLC does not endorse this product or attest to the accuracy of any manufacturer claims.