This section is from the book "An Elementary Outline Of Mechanical Processes", by G. W. Danforth. Also available from Amazon: An elementary outline of mechanical processes.
This machine is used to cut square or rectangular holes in wood. It consists essentially of a vertical shaft which is made to oscillate in the direction of its length, and which carries a heavy chisel at the lower end. Mortising machines are often worked by the pressure of the foot, without machine power.
 
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