Undercut (manufacturing)

In manufacturing, an undercut is a special type of recessed surface that is inaccessible using a straight tool.

In printed circuit board construction, it refers to the portion of the copper that is etched away under the photoresist.

They are often used at the end of the threaded portion of a shaft or screw to provide clearance for the cutting tool.

Undercut - Any indentation or protrusion in a shape that will prevent its withdrawal from a one-piece mold.

The corners may be undercut to remove the radius that is usually left by the milling cutter this is commonly referred to as a relief.