Thread Go-No-Go Ring Gauge

Thread Go-No-Go Ring Gauge

Thread go-no-go ring gauge is a measuring tool specially used to detect the dimensional accuracy and integrity of external threads.It consists of a thread go gauge and a thread no-go gauge,and is a core tool for quality control in thread processing,widely used in mechanical manufacturing,pipeline connection,fastener production and other fields.

Different from the smooth go-no-go ring gauge,the inner hole of the thread go-no-go ring gauge is processed with a complete thread profile matching the measured thread.The thread size of the go gauge corresponds to the maximum material profile of the external thread of the workpiece(including the upper deviation).The thread profile is complete and can cover the entire length of the thread,which is used to check whether the functional diameter and major diameter of the thread are within the qualified range.A qualified external thread should be able to be smoothly screwed into the thread go-no-go ring gauge without obvious obstruction during the screwing process.The thread of the no-go gauge corresponds to the minimum material profile of the external thread of the workpiece(including the lower deviation),and is usually a truncated profile(the thread height is about 1/2 of the standard thread height).It is only used to check whether the single diameter of the thread is out of tolerance.The screwing length of a qualified external thread with the no-go gauge should not exceed 2-3 threads(slightly different according to the thread specification).If it can be completely screwed in,it is judged as unqualified.

In terms of material,thread go-no-go ring gauges are mostly made of alloy tool steel(such as Cr12MoV,W18Cr4V)or high-speed steel.After forging,quenching and low-temperature tempering,the hardness can reach HRC58-63 to ensure the wear resistance and dimensional stability of the thread profile.High-precision ring gauges will also be processed by precision grinding,so that the surface roughness of the thread is controlled within Ra0.1μm,ensuring the matching degree between the thread profile accuracy and the measured thread.

When in use,it is necessary to first clean the burrs,oil stains and iron filings on the thread surface to avoid damaging the ring gauge thread profile.During detection,first screw the go gauge into the external thread of the workpiece.If it can be easily screwed to the bottom without jamming,it indicates that the functional diameter and major diameter of the thread are qualified.Then try to screw the no-go gauge.If the screwing length does not exceed the specified number of threads(usually 2 threads),the thread accuracy is judged to be qualified.This judgment principle of"the go gauge can be screwed to the bottom,and the no-go gauge can be screwed in no more than the specified number of threads"can quickly screen out problems such as thread dimensional error,thread profile deviation and pitch error.

The specification of the thread go-no-go ring gauge must strictly match the measured thread,including thread system(such as metric,British,American),thread profile(such as triangular,trapezoidal,rectangular),pitch,nominal diameter,etc.For example,to detect the M10×1.5 metric coarse external thread,a thread go-no-go ring gauge of the corresponding specification M10×1.5 is required.In the production of parts with external threads such as bolts,lead screws and pipe joints,it is a key tool to ensure the reliability and interchangeability of thread connections,which can effectively avoid assembly difficulties or connection failure caused by insufficient thread accuracy.