The cutting edge of a planer tool is called the planer blade. It is a removable part of the planer, allowing users to sharpen, replace, or otherwise change blades for different conditions and projects. Planer blades act much like the blade of a shaving razor, scraping off uniform layers of wood in order to create an even, smooth surface. Numerous types of planer blades are used in wood working to flatten wood edges, decrease the thickness of wood, or to create a uniform curve for tabletops, chair edges, or moldings.
In terms of size, planer blades vary depending on the specific planer used. Manual bench planers, the most common planer dating back to antiquity, range in size from as small as 5 inches (12.7 cm) up to nearly 2 feet (60.96 cm) in length. Modern power planers commonly measure less than 1 foot (30.48 cm) in length, but longer options are available for specialty tools. With so many planer tool size options, planer blade lengths naturally vary. Other characteristics of planer blades vary as well, including the type of metal, blade shape, and overall thickness.
Carbide or various types of steel are the preferred materials for blades. Blades made of carbide or featuring carbide-tipped edges allow for planing of harder woods, due to the increased strength and heat resistance of the material. High-speed or laminated steel planer blades provide agility, reduced cost, and the ability to sharpen the blades repeatedly before requiring replacement. Antique manual planers often feature blades made of iron, although replacement blades are difficult to fit for such tools.
Depending on the specific type of planer, the actual features of planer blades differ. For example, hand planers used to manually shape or shave wood have thin, flat blades set in a wood or wood-and-metal housing. Power planers, by contrast, use planer blades known as knives. Planer knives are generally thicker than manual planer blades, with a longer cutting edge. Metal housings for power planer knives provide the improved stability required for a power tool, especially in commercial applications.
In addition to standard manual or power planer blades, options exist for blades that round wood edges, create distressed surfaces, and provide other custom wood working choices. Spiral planer blades have beveled edges with a scalloped shape to create uneven, distressed, or antique-looking surfaces. Rabbet, shoulder, and finger plane blades create rounded edges, steps, or allow for working on very small wood pieces such as musical instruments or toys. Such specialty blades require special planers.