Formerly Emhart Teknologies & Infastech

Key Locking Threaded InsertsKey Locking Threaded Inserts


  • Insert body – Stainless Steel, Grade 303 or alloy A286 (140 ksi min)
  • Keys – Stainless Steel, Grade 302

Finish Options

  • Coating / Plating – As Required, Passivation
  • Lubrication Option – Dry Film Lube, Silver

Added Benefits of Spiralock® combined with the key staking feature

  • Free-spinning bolt assembly
  • High strength and reliability
  • No tang to break off after installation
  • Preload locking with the application of torque
  • Significantly increases torque-down and load capability in weaker materials
  • Keys eliminate rotational movement of insert within parent material
  • Hole preparation with standard drill and tap
  • Impossible to cross thread during installation
  • No special prewinder, free spinning installation

MS51831 / NAS1395 Spiralock commercial equivalent


Spiralock Part Number Spiralock Internal Thread Size* External Thread Size (Modified) Material Coating MS Series Equivalent
FE06-32-0048 6-32 12-28 SS303 Passivated MS51830-103 (Mini)
FE08-32-0025 8-32 1/4-28 SS303 Passivated MS51830-104 (Mini)
FE08-32-0049 8-32 5/16-18 SS303 Passivated MS51831 (HW)
FE10-32-0059 10-32 5/16-18 SS303 Passivated MS51830-201 (LW)
FE10-32-0063 10-32 3/8-16 A286 Dry Film Lube MS51831CA201L (HW)
FE10-32-0067 10-32 5/16-18 SS303 Dry Film Lube MS51830-201L (LW)
FE10-32-0071 10-32 3/8-16 SS303 Dry Film Lube MS51831-201L (HW)
FE10-32-0072 10-32 7/16-14 SS303 Dry Film Lube MS51832-201L (EHW)
FF0250-28-0055 1/4-28 3/8-16 SS303 Passivated MS51830-202 (LW)
FF0250-28-0057 1/4-28 3/8-16 A286 Dry Film Lube MS51830CA202L (LW)
FF0250-28-0058 1/4-28 3/8-16 SS303 Dry Film Lube MS51830-202L (LW)
FF0250-28-0059 1/4-28 7/16-14 A286 Dry Film Lube MS51831CA202L (HW)
FF0250-28-0062 1/4-28 3/8-16 4140 Cadmium MS51830A202 (LW)
FF0250-28-0064 1/4-28 7/16-14 SS303 Dry Film Lube MS51831-202L (HW)
FF0250-28-0065 1/4-28 1/3-13 SS303 Dry Film Lube MS51832-202L (EHW)
FF0500-20-0025 1/2-20 11/16-11 A286 Passivated MS51831CA206 (HW)
FF0375-16-0040 3/8-16 9/16-12 SS303 Passivated MS51831-104 (HW)
FF0375-24-0051 3/8-24 1/2-13 SS303 Dry Film Lube MS51830-204 (LW)
FM0050X080-0019 M5 x 0.08 M8 x 1.25 SS303 Passivated NA0148 (LW)
FM0120X125-0025 M12 x 1.25 M18 x 1.5 SS303 Passivated NA0149 (HW)


Mini: Miniature / LW: Lightweight / HW: Heavyweight / EHW: Extra Heavy Weight

* Metric sizes available upon request

Other sizes and materials are also available upon request