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TEMPLUG is a temperature sensitive steel set-screw and is used for determining the maximum temperature in locations that are difficult to instrument using conventional "thermocouple type" techniques (moving engine parts, turbine blades, and bearings are good examples of typical applications). The part being tested does not need to be made of steel; nickel alloys, aluminum, composites, ceramics can be tested with this technique. By drilling and tapping, a TEMPLUG can be installed directly into the location at which temperature needs to be measured. Under suitable conditions, TEMPLUG can measure maximum temperatures accurate to within ± 3%. 
TEMPLUG was developed in the early 1970's in a joint effort by TESTING ENGINEERS, INC. & "SHELL RESEARCH LTD.". They function on the relatively simple principle of thermal tempering (thermal softening) of a hardened steel. There are two types of plugs differing in material composition, making them suitable for different temperature ranges. TEMPLUG is also available in two sizes M3 and M1.6 

Type Size Dimensions Temp. Range



Length Diameter

° F

° C

2 M3 4mm 3mm 165 - 1,200 62 - 649
3 M3 4mm 3mm 1,020 - 1,565 550 - 852
2 M1.6 2mm 1.6mm 165 - 1,200 62 - 649
3 M1.6 2mm 1.6mm 1,020 - 1,565 550 - 852

  View or Download TEMPLUG User Manual (PDF Format)


M1.6 TEMPLUG with installation handle


Drilled and tapped holes, ready for TEMPLUG installation

M3#2 TEMPLUG being installed

M1.6 TEMPLUG and two turbine blades
For More Information on the proper TEMPLUG for your application
contact Maria at 510-835-3142 ext. 177 email: mariar@testing-engineers.com