Thread Gauges for Precise Thread Inspection | ULTRA Shop

Buy high-precision thread limit plug gauges, thread go ring gauges, and thread no-go ring gauges from ULTRA for all international thread standards for reliable quality control online.

Thread gauges from ULTRA form the reliable foundation for rapid, process-secure go/no-go inspection of internal and external threads directly within industrial series production and quality assurance. This standardized gauging procedure ensures compliance with international tolerance classes and guarantees that screw connections fit together perfectly and function reliably in their final application.

Basic Knowledge of the Inspection of Cylindrical Threads

The dimensional inspection of threads using mechanical gauges is strictly separated according to metrological principles. A thread limit plug gauge or a pair of thread ring gauges always consists of a go side and a no-go side, which check different physical properties of the thread.

The go side must be able to be screwed into or onto the entire length of the workpiece thread by hand without undue force. It inspects the so-called virtual pitch diameter. This means it controls not only the pitch diameter but simultaneously checks the thread form as well as any errors in the thread pitch or the partial flank angle.

The no-go side is recognizable by its characteristic red marking and features a shortened thread profile approach. It must not be able to be screwed more than two turns into or onto the workpiece thread. It exclusively checks whether the minimum limit of the pitch diameter has been undershot or the maximum limit has been exceeded at any single point.

Consideration of Surface Coatings in the Manufacturing Process

In modern production technology, threads often need to be electroplated, phosphated, or otherwise coated. Since these layers subsequently thicken the material, we offer specific thread gauges upon request that are precisely designed for pre-coating size and finished size testing. This enables reliable tolerance control both before layer application and during final standard-compliant quality control.

Custom Dimensions and Express Rapid Customer Service for Industry

Our B2B portfolio seamlessly covers all common thread types, from metric ISO threads and tapered Whitworth and pipe threads, British and American threads. For customized intermediate sizes, pitches, or deviating tolerance classes, we kindly request your inquiry. All thread gauges guarantee seamless, traceable calibration to national standards through optional factory or DAkkS certificates.