<P> Files have forward - facing cutting teeth, and cut most effectively when pushed over the workpiece . A variety of strokes are employed to stabilize the cutting action and derive a varied result . Pulling a file directly backwards on a workpiece will cause the teeth to dull . Draw filing is an operation in which the file is grasped at each end, and with an even pressure alternately pulled and pushed perpendicularly over the work . A variation involves laying the file sideways on the work, and carefully pushing or pulling it across the work . This catches the teeth of the file sideways instead of head on, and a very fine shaving action is produced . There are also varying strokes that produce a combination of the straight ahead stroke and the drawfiling stroke, and very fine work can be attained in this fashion . Using a combination of strokes, and progressively finer files, a skilled operator can attain a surface that is perfectly flat and near mirror finish . </P> <P> Pinning refers to the clogging of the file teeth with pins, which are material shavings . These pins cause the file to lose its cutting ability and can scratch the workpiece . A file card, which is a brush with metal bristles, is used to clean the file . (The name, "card", is the same as used for the "raising cards" (spiked brushes) used in woolmaking .) Chalk can help prevent pinning . </P>

Where did the name bastard file come from