I came across this in a friend's garage and am puzzled as to what it could be. It slides back and forth and can lock into place using grooves.
Does anyone know what it is?
It looks like a type of tool used in drafting to enlarge or reduce the size of a drawing. Depending on where the pivoting point is locked, you would trace over a drawing with one end of the instrument and the other end would have a graphite tip and would draw the lines on another sheet of paper. I just can't think of the name of the instrument, but I believe that it starts with a "P".
The tool that I was thinking of is a Pantograph.