Threaded workpiece 1 is placed on supports 2 and is held tightly against locating member 3 between two measuring rollers 4 and 5. Roller 4 is mounted in yoke 6 which is linked to the stock by four flat springs. Roller 5 is linked in a similar manner to block 7, which is mounted on vertical springs, enabling the block to be displaced horizontally. Spring 8, whose force can be regulated by screw 9, holds the rollers against the thread of workpiece 1. In checkinig the thread, roller 5 and block 7 are in a strictly definite position corresponding to the actual value of the pitch diameter of the workpiece thread. The position of block 7 determines the clearance between insert 10 and measuring nozzle 11 to which air is delivered from flow gauge 12. Depending upon this clearance, the flow of air is varie through flow gauge 12, varying the height at which the lightweight float indicator is held suspended in the internally tapered glass column. The flow gauge scale is graduated in units showing deviation in size of the thread pitch diameter. The stock and locating member can be adjusted to accommodate thread of various sizes.
$4282$CHP,M$