Checking the size of the bored hole (to hold the main spindle bearing) in the rear of a headstock casting

An apron backplate being checked with a dial indicator to ensure that the holes for the power-feeds' shaft are perfectly in line.

Machined gear blanks are checked by an inspector for uniformity of diameter, width of face and bore sizes. Although a micrometer is being used for the benefit of the photographer the "fixed" and "go-no-go" plug gages on the bench would have been the normal tools employed

Selective assembly: in the foreground the bore of bearings to be used on the main headstock spindle are checked: in the mid-ground the diameter of a spindle's trunnion surface is measured and in the background a row of spindles, complete with their bearings.