"Star Turn" surface hardness comparator in bakelite case. Used to measure the hardness of materials as measured in the Rockwell C scale.

The measurement is made by rubbing pins across materials, until one pin scratches and one slides; the hardness of the material is the measurement between the two pins.

Physical Description

Consists of 9 steel spikes radiating from a bakelite base. Marked from 46 to 62 on each face of bakelite base. Base has star motif at centre. Bakelite cover is labelled "STAR TURN" with star motif in centre, and 9 lines radiating outwards. Registration number has not been painted on object See also Trade Literature.

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