I designed a compact knife sharpener using the ceramic rods salvaged from a broken Harbor Freight “GORDON Handheld Knife Sharpener.” The rods are arranged for sharpening a 20° blade angle, and the entire unit measures just 20 mm × 20 mm × 20 mm. While it can be used handheld in a pinch, it’s more secure to clamp it in a bench vise.

By drastically reducing the size of the original sharpener, this mini version is easier to handle and store. The ceramic rods can also be repositioned, so wear isn’t concentrated in one small area like in the original design. Since there’s no metal involved, rust is no longer a concern—meaning this little sharpener can be used almost indefinitely.