VERIFYING THE VARIATION IN THREADED SETTING PLUG PITCH DIAMETER TRANSFER TO CONTACT MATED INTERNAL THREAD BY MEASUREMENT AND CALCULATION, INCLUDING FUNCTIONAL SIZE ANALYSIS

摘要

Transfer of groove diameter from external thread mated to an internal thread exceeds industrial claims. The simple Jeffcott C correction accompanying the thread wire calibration is only reliable for X and W tolerance for lead and flank angle on threads. Present procedures for measuring groove diameter, calculating pitch diameter and functional size need clarification. A method for determining the true pitch diameter of a mated internal thread (assembly size) is introduced and may be a reliable method to asses the accuracy of measured screw thread characteristics.