Accurately Senses Loads Induced in Studs

Detects Overloads in Assembled Equipment

Inexpensive Force Link Transducer

STRAINSERT ST Series Standard Studs employs an exclusive internal gaging technique (U.S. Patent #2,873,341) to detect the loads induced in them. This technique consists of the installation of foil type strain gages inside a small hole drilled along the longitudinal neutral axis of the Stud. This is far superior to the usual external gage installations both in mechanical and environmental ruggedness. Furthermore, a neatly miniaturized packaging is achieved by using the Stud itself to protect and seal the strain gage circuit. Still, this arrangement compares very favorably with the best external gage installations in accuracy and stability. Strainsert Studs, along with other internally gaged fasteners, were the first to provide the means for direct, accurate, and independent inspection of assembled structures under simulated or actual service conditions. Vibration and Shock loads, as well as static loads, on such assemblies can be easily measured to determine their structural reliability and integrity.

The ST Studs can also be used as inexpensive force transducers in many instances.

Type C – screw type miniature connector, requires mating cable assembly.

Type H – multi-pin header for soldered lead wire connections

Type W – factory installed cable

Over 90 different STRAINSERT Series ST Studs are stocked, ready for gaging.
Unit of Measure



N/A Stressproof, La Salle Steel Co.


N/A Rockwell C22 to C30

Ultimate Tensile Strength

N/A 125,000 psi approx. ultimate

Yield Strength

N/A 100,000 psi


N/A Class 2A, machined


N/A Black Oxide


N/A Load & Unload Calibration Load Only Calibration (Standard)

Performance Specs

Gages Type

N/A Metal Foil

Gage Factor (Nominal)

N/A 2.00


N/A ±1% of Allowable Load


N/A ±0.1% FS


N/A 350-ohm (Standard) FB: 12V (Maximum)
350-ohm (Standard) QB: 6V (Maximum)
120-ohm FB: 3V (Maximum)


N/A Full Bridge Strain Gage Circuit (Standard) Quarter Bridge Strain Gage Circuit

Bridge Resistance (Nominal)

N/A 120 Ω 350 Ω (Standard)

Service Temperature

N/A 150°F (Standard) 300°F (Max.)

General Information

N/A Strainsert fasteners utilize an exclusive internal gaging method (U.S. Patent #2,873,341) to indicate bolt tension due to preload and subsequent service loads with strain gage accuracy. They are the first fasteners to provide a means for accurate, independent inspection of an assembled bolt for preload, thereby enhancing the structural integrity and reliability of both the bolt and the assembly.


  • Measurement of preload induced in fasteners
  • Accurate tightening of fasteners within 1% of induced load
  • Uniform tightening of fasteners in a bolt pattern