Thread Elongation Gauge

With the help of the stainless steel thread elongation gauge can be checked if a thread is deformed by too much tensioning. The tensioning is mainly caused by excessive temperature changes and dynamic stresses.

The thread elongation gauges are designed such that can be directly detected how much percentage the amount of elongation is and whether this relates to rejecting or approving the thread.

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When using bolts and nuts of common grade for fasteners up to M30 (1 inch) diameter, the use of new bolts and nuts is recommended when bolt-load control methods such as torque or tension are deemed necessary. For larger diameters, it is recommended that the cost of cleaning, deburring, and reconditioning be compared to the replacement cost and considered in the assessment of critical issues of the assembly.

In addition to Inspection Level 21 according to ASME B1.3M (designed to guarantee functional assembly of male onto female threads, plus functional size control of maximum material limits) the thread elongation gauge is developed to check an extra characteristic.

The 0.2% yield strength (or proofload) is the stress at which 0.2% plastic deformation occurs. This offset yield point is according to ASTM, while in the industry also 0.1% and 0.5% are used. In essence, the 0.2% yield strength method provides achievable values that can be measured. However, it is an approachable measure, which is accepted in the technical sense, and extends from the transition form elastic to the beginning of the plastic deformation.


Thread Elongations Gauge by Flange Management
1% extension scale
Thread Elongation Gauge. 8 Threads Per Inch. 0-1 Percent.
0.1% extension scale


According to ASME (Unified Inch Screw Threads). All sizes are available in 1% and 0.1% extension scale.

  • 4 threads per inch
  • 4.5 threads per inch
  • 5 threads per inch
  • 6 threads per inch
  • 7 threads per inch
  • 8 threads per inch
  • 9 threads per inch
  • 10 threads per inch

Thread form according to DIN (Metric Screw Threads). All sizes are available in 1% and 0.1% extension scale.

  • 2.5 mm pitch
  • 3 mm pitch
  • 3.5 mm pitch
  • 4 mm pitch
  • 4.5 mm pitch
  • 5 mm pitch
  • 5.5 mm pitch
  • 6 mm pitch
  • 8 mm pitch