Woodworking Tips: Using Files and Rasps

Curved shapes in wood are usually cut with a band saw, a jigsaw, a saber saw, or any of the handsaws capable of cutting a radius. Irregular shapes and reliefs are sometimes chiseled or gouged out by hand. All of these methods leave a surface made up of small irregular cuts that must be smoothed out. Wood files and rasps are the tools used for this purpose.

Files with single-cut teeth (that is, teeth that cut in one direction) will produce a smoother surface than double-cut files. Rasps and double-cut files, however, are less prone to clogging than single-cut files. Files and rasps are available in four grades – coarse, bastard, second, and smooth. A four-in-hand rasp combines all four on the slightly rounded surfaces of a single tool. Some carpenters prefer the finer metal files for smoothing wood, even though they clog more easily.

The plane’s blade is stamped out of sheet metal and then ground in such a way that the surface is covered with small cutting edges. The plane is available with a variety of handles that designed to hold blades of different shapes. The blades should be replaced when they become dull.

They key to success when using files (or any other smoothing tool) is to keep the wood from chattering, or vibrating, as you work. Secure the piece with a vise or clamp; use side supports if it is thin. If the wood chips or splinters when you work the end grain, clamp a bit of scrap against (and level with) the splintering edge. Always make sure that your files are sharp.

Rifflers are small files or rasps. They come in a great variety of sizes and shapes. Use them to smooth the hard-to-reach areas created in wood carving. They are also useful for cleaning out the small rounded corners left by the router bit. Small curved and irregular areas can also be smoothed with any one of several attachments to an electric drill, including rotary files, rotary rasps, and even a drum type of tool.