Load-Sensitive Column for a Strain-Gauge Load Cell

Saw a length of round bar. Center both ends, fit a lathe dog and face both ends square.

Rough-turn to within 0.03–0.04 in of size, then take the finishing cut slowly, with cutting oil. Ruge allows round, square, solid or hollow; a square section (filed or shaped flat) takes the gauges more easily.

Cut a thread on the lower end so it screws rigidly into the base. Round the upper end to a half-sphere with a form tool and file.

Ruge's patent gives the part's shape and job but no material or size. Mild steel and silver-solder brazing are our choice; size it to the load you need. Lathe method after Palmateer, Elementary Machine Shop Practice (1918).