A set of two General Electric surface-roughness gauges. The gauges, each 15 cm in length, are stored in a leather pouch and show surfaces machined to an average surface roughness ranging from 4 micro-inches to 200 micro-inches. The gauges are manufactured by General Electric and the instructions engraved into them suggests that one should make a “comparison by sight and feel” according to GE instruction GEJ-1136. The finer-finish gauge shows a catalogue number 342X60 while the coarser-finish gauge is catalogue 343X61. The gauges were used by draftsmen and engineers to specify an acceptable surface roughness on drawings for the construction of a component.
