Each carpenter uses a Surform file or woodworker's file wood and a regular file for work on his tools. But filing woodwork is usually not regarded good practice. The Surform tool or file is employed to expand round holes and also to finish curved work that has been sawed near to the line. To the craftsman, this is permissible only when the work is exceedingly hard to reach using a chisel or a spokeshave. When working with the Surform tool or file, grasp it at the level of your elbow. The handle must be held in the right hand onthe fleshy part of the palm, with the thumb leading on top. The front end of the tool should be held using the thumb and first two fingers of the left hand, with the thumb on top. These tools are designed to cut in only one direction, so that pressure must be placed only on the forward stroke.
All files should be worked using the handle, except when a file is employed for jointing a saw. A lot of accidents happen when a file without a handle encounters resistance and the tang pierces the handler's skin. Handles are available in metal and wood and are normally removed when the file is not being used. To put a small handle, insert the file with the handle on the bench, hitting the point until the fit is firm. Be mindful not to strike too hard, or the handle would split. To take out the handle, put the ferrule at the edge of the bench so that the handle is over the bench and the file is free; then tap the file against the bench.
To create finishingcuts on long, narrow work, clutch the tool at a right angle and move it to and fro. This is known as draw filing.
When filing a curve, use a sweeping movement diagonally across the grain to avoid creating grooves and hollows in the work. This likewise tends to avoid chipping both edges.
The teeth of a Surform tool are fragile and easily broken. Careless wielding of files would dull them. The oil on a new file can be taken away by covering it with chalk or charcoal prior to using.
Files will last a lot longer if they're cleaned with a file Card or brush each time they're used. This doesn't sharpen the file but would restore its usefulness. A file used on metal will soon go dull because of the gathering of filings. These can be removed by dipping the file in a solution of sulphuric acid for five minutes, then washing it in ammonia. The acid gnaws at the clogging fill and loosens them enough to let them to fall out.
The wood rasp is a rough-cut file designed for cutting wood, has one flat side and one convex side, either of which closely toothed. One end is a tang that fits into a wood handle. Surform tools have mostly replaced the rasp modern usage.
The rasp is utilized for cutting and dressing joints where a plane cannot be used, and for dressing handles in handle fitting. Oil should not be used on a rasp because it will cause the rasp to become congested with wood particles.