A system used to measure the simple pitch diameter of internally
threaded holes and fasteners.
QUEST
has significant experience in application of the LOTIS®
inspection technology to threaded holes.QUEST is the only company that has developed
non-contact methods for measuring the simple pitch diameter of internally threaded surfaces.
An overview of thread inspection work is summarized in the article entitled "Non-Contact Internal Thread Inspection" published
in the Proceedings of the 1999 SAE Aerospace Automated Fastening Conference.
The first system developed
by QUEST was for General Dynamics Land Systems Division.The primary interest
was tracking tool wear for ¾-10 threaded holes.There were several hundred of
these holes in the body of the vehicle and General Dynamics wanted to detect when the tooling needed to be changed.If a tap or drill bit broke, particularly if it were lodged in the vehicle body, it was very costly to
pull the vehicle off the production line and remove the broken tool.The thread
measurement tool is self-contained in that the mechanism for inserting and rotating the probe is part of the probe mechanism.The system automatically collects several equally spaced axial slices along the length
of the threaded hole and combines the data to calculate the simple pitch diameter and minor diameter for each thread crest
and root.
Two similar thread measurement systems were designed for QC Laboratory
use; one with a measurement probe diameter of 7 mm and one with a measurement probe diameter of 16 mm.The 16 mm probe has a larger measuring range to be used for larger threads.The 7 mm system was developed for the National Institute for Standards and Technology (NIST) and the 16 mm system was
developed for DoD to inspect mortar end caps.
