I use these. Work great.
FLEXBAR 16707 .018
BenefitsAn accurate and inexpensive way to check threads.Makes thread triangles, thread Micrometers and all other current methods obsolete.ApplicationsAs easy as selecting the proper wire sizes, matching the wire size with the proper P.D. Check, slipping two wires into the holder, placing the...www.travers.com
I worked out a procedure to measure thread pitch diameter with a single wire. I basically involves measuring the O..D of the thread and measuring the diameter plus a wire.