surface gage vs surface gauge

surface gage and surface gauge both are nouns.

Word	Noun	Adjective	Verb	Adverb
surface gage	Yes	No	No	No
surface gauge	Yes	No	No	No

As nouns, surface gage and surface gauge are synonyms defined as:

surface gage and surface gauge: gauge consisting of a scriber mounted on an adjustable stand; used to test the accuracy of plane surfaces

Other synonyms of surface gage include scribing block.

surface gage (noun)	surface gauge (noun)
gauge consisting of a scriber mounted on an adjustable stand; used to test the accuracy of plane surfaces	gauge consisting of a scriber mounted on an adjustable stand; used to test the accuracy of plane surfaces