HELICOIL INSERT LENGTH SELECTION

Helicoil Insert Length Selection Calculator has been developed by using ASME B18.29.1 – 1993 standard (Helical Coil Screw Thread Inserts – Free Running and Screw Locking (Inch Series)) and NASM 33537 standard (Insert, Screw Thread, Helical Coil, Inch Series, Coarse and Fine Thread, Standard Assembly Dimensions for) and will aid to calculate the helicoil insert length selection to develop the full load value of the bolt rather than stripping the tapped material.

The length of engagement of a bolt in an insert is generally determined by strength properties. The engineering practice of balancing the tensile strength of the bolt material against the shear strength of the boss material also applies to helicoil inserts.

Calculator:

INPUT PARAMETERS
Standard to Use
Parent Material
Shear Strength (psi)
(Aluminium, Magnesium, Steel)
Bolt Designation


Note : When parent material shear strength falls between two tabulated values, use the lower of the two.

Note: The parent material shear strengths are for room temperature. Elevated temperatures significantly reduce shear strength values; compensation should be made when required.

Note: Bolt thread length, overall length, insert length, and full tapped thread depth must be adequate to insure full thread engagement when assembled in order to comply with its design function.

 


RESULT
Parameter Value
Lengths of Thread Engagement
in Terms of Diameters
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Definitions:

Helicoil Insert: Helicoil inserts are screw thread bushings coiled from wire of diamond shape cross-section. They are fit into thread tapped holes to form internal threads with nominal size.

Reference:
  • ASME B18.29.1-1993, Helical Coil Screw Thread Inserts - Free Running and Screw Locking (Inch Series)

  • NASM 33537, Insert, Screw Thread, Helical Coil, Inch Series, Coarse and Fine Thread, Standard Assembly Dimensions for