Smooth Go-No-Go Plug Gauge

The smooth go-no-go plug gauge is a special measuring tool used to check whether the inner hole size of a workpiece meets the tolerance requirements.It corresponds to the smooth go-no-go ring gauge:the former is used for inner hole detection,and the latter for outer circle detection.Together,they form the basic tool combination for dimensional inspection of cylindrical workpieces,widely applied in mechanical processing,mold manufacturing,auto parts production and other fields.

Its structure consists of two parts:a go gauge and a no-go gauge,both of which are cylindrical plugs.The outer diameter of the go gauge is equal to the minimum material size of the measured inner hole(i.e.,lower deviation),ensuring that the minimum size of a qualified inner hole allows the go gauge to pass through smoothly;the outer diameter of the no-go gauge is equal to the maximum material size of the measured inner hole(i.e.,upper deviation),which is used to limit the maximum size of the inner hole,and a qualified inner hole should not allow the no-go gauge to pass through.The working surface is processed by precision grinding and lapping,with a surface roughness of up to Ra0.02μm,and the outer diameter tolerance is strictly controlled within IT3-IT5 grades,ensuring the reliability of detection accuracy.

In terms of material,smooth go-no-go plug gauges are mostly made of high-carbon tool steel(such as T10A)or alloy tool steel(such as Cr12MoV).After quenching,their hardness can reach HRC60-65,featuring excellent wear resistance and dimensional stability.Some high-precision plug gauges also undergo low-temperature aging treatment to eliminate quenching stress and prevent dimensional drift during long-term use.

When in use,it is necessary to first clean the inner hole of the workpiece and the outer surface of the plug gauge to avoid impurities affecting the detection result.Insert the go gauge into the inner hole of the workpiece;if it can pass through smoothly without obvious jamming,it indicates that the inner hole size is not smaller than the minimum limit;then try to insert the no-go gauge;if the no-go gauge cannot be inserted or can only be partially inserted,the inner hole is judged to be qualified.This judgment principle of"the go gauge passes,the no-go gauge does not"is simple and intuitive to operate,without the need to read specific values,which greatly improves the detection efficiency.

The specification of the smooth go-no-go plug gauge must strictly match the measured inner hole,and there are various models divided according to the nominal diameter and tolerance grade.For example,to detect an inner hole with a diameter of 10mm and a tolerance grade of H7,a smooth go-no-go plug gauge of the corresponding specification is required.In the production of inner hole parts such as bearing holes,sleeve holes,and bolt holes,it is an important tool to ensure product interchangeability,especially suitable for rapid quality screening in production lines.