Today one client from Singapore complained one problem, who have bought both 1/2-10 ACME thread ring gauge and thread plug gauge from us . he said: “We have received customer’s  Ring gauges  ½-10 had been using in their production line, your thread gauge “Go” side is  totally cannot enter to the Ring gauge, what is the reason that you said is right? Can you refer to the website base on the international standard specification for ½-10?If you claim that your thread gauge size is right and it  should matching with the Ring gauge.”

If yes, the plug gage will fix with the ring gage, then we will have big problem. thread plug gauges are used for checking internal threads,ring gauges are used for checking external threads. Internal threads’ pitch diameter tolerance range is above 0 line, external threads pitch diameter tolerance range is below 0 line. the screw thread can be turned into only when the inside is big and the outside is small. Plug gages GO ends manufacturing tolerance range is in the pitch diameter tolerance range of internal threads, ring gages GO end manufacturing tolerance range is in the range of external pitch diameter tolerance, then the size of plug gages’s GO end is bigger than the size of ring gages’GO end, of course the plug gage can’t be turned into ring gages. it is the setting plug gages used to inspect the ring gages.

Here I have to clear that plug gage can’t be used for testing ring gauges. same size’s ring and plug gauge can’t be used for testing each other. there is no need the plug gauge’s go end should go through the ring gauge. or it should matching with the ring gauge.  plug gauge’s GO and NOGO ends are used for testing interior thread of work-pieces.  ring gauges’ GO and NOGO ends are used for testing exterior thread of work-pieces. both ring gauge and plug gauges are for testing goods’ thread. thread plug gauges and thread ring gauges can’t be fixed together. If they are fixed together, both gauges have the possibility of wear and tear. SO every client should be careful and not fix them together.  plug gauges’ GO end should go through the whole thread of interior thread and go till to the thread end. the ring gauge’s GO end also need like this.  the plug gauges’ NOGO should be stopped in the thread. the best condition is the NOGO stop between the 1-2 turns. In the CNC machining industry, some clients who ask for strict quality sometimes ask for the gauge’ NOGO should stop between 1 1/2-1 3/4 turns.

Updated on Data: 8th. SEP.2017