dial gauge when measuring shaft with cogwheel

16x9 abstract accuracy background black blue circle closeup cog cogged cogs cogwheel control curve detail device dial digit distance engineering equipment exactness gauge gear gearwheel hand holder idea indicator industry instrument involute iron laboratory machinery measure measurement measuring mechanical mechanism metal metallic micrometer needle nobody nopeople part parts plastic pointer precision probe quality red repair research round scale shaft skilled spare steel technical technology teeth test thread tolerance tool toothed wheel when white work