Elliptical cutting frame

This is an elliptical cutting frame working on the principle of the elliptical trammel. It is adapted to fit into a slide-rest of an early pattern and was probably made about 1800.

Attached to the front end of the frame in an adjustable position is a steel framework containing two slideways at right angles to one another. The drive is taken from a pulley at the rear of the spindle to a pin which moves in the first slideway through slotted links which allow free lateral movements. The pin is fixed to one part of an adjustable slide, the other part of which passes through a gunmetal block sliding in the second or vertical slideway and is fixed to a plate carrying the cutter frame. The eccentricity of the tool in the cutter frame is adjustable by a thumbscrew and, by altering this eccentricity and the eccentricity of the sliding pin, ellipses of varying sizes and proportions may be obtained.