Compressed air is delivered through the measuring chamber into the self-aligning measuring head. Sleeve 2 with passage a for air flow is pressfitted into body 1 of the head. Cylindrical nozzle 3 is secured on rubber membrane 4 which is held by nut 5 to body 1. The pressure of the air from the measuring head bends the membrane, setting the nozzle properly with respect to the surface whose roughness is to be measured. Spring 6 holds nozzle 3 against the surface, properly aligned regardless of the position of supporting nut 5. The pressure in the measuring head, determined by a water-column manometer, indicates the height of the surface irregularities of the work.
$4050$EHP,M$