PMC Mercury Adjustable Thread Ring Gages are manufactured from selected steel, machined and precision lapped and then meticulously inspected in every thread element. We set our rings with our high quality Thread Setting Plug Gages or Hilo Setting Plug Gages. Not Go ring gages are distinguished by a groove around the outside diameter. Setting plug gages should be ordered at the same time as ring gages to ensure proper mating. Pitch Diameter of adjustable thread ring cannot be taken as a direct measurement. The functional pitch diameter is transferred by the setting plug to the ring gage. The ring gage setting is unique to the particular setting plug gage and cannot be expected to be duplicated on any other setting plug gage without readjustment. The functional pitch diameter of any two given setting plugs both known to be within tolerance specifications could vary by more than 0.0003” from each other. Also, the relative “feel” of the inspector setting the ring gage plays a major role in the evaluation of this attribute. All our information is taken directly from the American Measuring Tool Manufacturers Association.
Our Handbook is the number one resource for everything you need to know about Thread Measuring Wires and is a great reference guide for any shop or laboratory. Tables, specifications and examples of gears including external gear, internal gear with varying pressure angles are referenced in the Handbook.