The compound rest is generally used for turning or boring short steep tapers, but it can also be used for longer, gradual tapers, providing the length of the taper does not exceed the distance the compound rest will move upon its slide. This method can be used with a high degree of accuracy, but is somewhat limited due to the lack of an automatic feed and the length of the taper being restricted to the movement of the slide.
The compound rest base is graduated in degrees and can be set at the required angle for taper turning or boring. With this method, it is necessary to know the included angle of the taper to be machined. An included angle is formed by and between two intersecting straight lines.)
The angle of the taper with the centerline is one-half the included angle and will be the angle that the compound rest is set for. For example: To true up a lathe center which has an included angle of 60 from parallel to the ways If the taper is given in taper inches per foot, the angle for the compound rest setting will have to be computed or taken from an appropriate taper sizes and angles table.