Left hand thread gages are used for checking Left hand thread. Left hand threads are designated LH. They are relative to right hand thread( RH). The thread is with counter-clockwise rotation. A thread is a left hand thread, if when reviewed axially, it winds in a counterclockwise and receding direction. The helix of a thread can twist in two possible directions. Most threads are oriented so that the threaded item when seen from a point of view on the axis through the center of the helix, moves away from the viewer when it is turned in a clockwise direction, and moves towards the viewer when it is turned counter clockwise.By common convention, right-handedness is the default handedness for screw threads. Therefore,most threaded parts and fasteners have right handed thread.we can produce kinds of left hand thread gauges,      For example, Metric, United Inch (UN), Trapezoidal, Acme etc. Not like the right hand thread gages, most of the RT  gages are in stock. Most of left hand thread gages need to be produced specially. Usually, the ring gages need two weeks to be finished, the plug gages need ten days to be finished. If clients need these LH gages with long form calibration certificate, we can send to Beijing Aerospace Institude for Metrology and Measurement Technology to get the certificates, which is ISO17025 accredited and ISO9001:2008 passed. Usually we need three days to get certificates.

A thread is a left-hand thread if, when viewed axially, it winds in a counterclockwise and receding direction. All left-hand threads are designated LH.

We produced thousands of left hand thread gages for clients all over the world. gaugestools provide high quality long wearing left hand thread gauges, each gage is 100% inspected, gaugestools meet ISO 9001:2000 and ISO/IEC 17025 requirements. our gauges made from oil hardened tool steel-Gcr15,  high wear resistance,  58-62 HRC. Our clients like our thread gauges very much, and give high praise to us. Here I list some left hand thread gages we produced recently.

•  1 ¼” -6 ACME-2G L.H. ring gauge and 1” -5 ACME-2G L.H. ring gauge
• M36x2 6g LH ring gage
• TR18 x 2-7e-LH Go/No Go Ring Gage
• . TR40x3 7e LH DIN 103   ring gage
• M13.5 x 1 LH Go/No Go plug gauge
•  M9 X 1.0 LH plug gage
• Thread plug gauge TR36x3 LH GO-NO GO
•   Thread ring TR36x3 LH GO and NO GO
• 1.375”-5 ACME (2G) Left Hand thread plug gage ASME1.5
• 1.625”-6 ACME (2G) Left Hand thread ring gage ASME1.5
• M13.5×1 4h5h-LH  ring gage

Our left hand ring gages are solid, clients can use them to turn on thread directly, not need any adjust, our left hand plug gages are  with taperlock style with GO NOGO double ends. We can produce kinds of thread forms LH gages fully according to clients’ requirements. Special size, speical class of fit, one, two or three starts etc all are available.     All our gages are with superior quality. Our gauges got certificates of UKAS lab, N.I.S.T lab. Our clients sometimes send our gages to their local lab to get calibration certificates, our gauges also can passed the test!

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In December,2017, we produced   Go and NoGo Ring for thread M 7 x 1,  also in 3g and this one in LH 

gaugestools is fully equipped with modern production facilities , including state-of-the-art  grinding machines and measurement systems. We can produce kinds of left hand thread gauges, including ring gauges and plug gauges. gaugestools guarantee flexibility and short lead to our customers both for standard and special items, there is no MOQ, welcome new and old clients to contact us for new requirements.

we produced 1″-14 UNS 2A LH thread ring gage and 1/2-13 UNS 2B LH left hand thread plug gage in June.2019

We produced many 2 stars ACME LH thread gages in December.2019. for example 2 3/4-0.333p-0.666L ACME 2G LH GO NOGO plug gauge