| Diameter | Pitch
(mm) | Thread Form | Length | Style | Material |
| 4 | 40 | UNC (Unified National Coarse) | 1.0D | Thread Locking - Tanged | Stainless Steel |
Length explained
The length of a wire thread insert is calculated as a multiple of the diameter:
e.g. M8 x 1.5D the insert length = 12mm;
e.g. M8 x 2D the insert length = 16mm
About our LOCKING Thread Repair Inserts
Sometimes referred to by the brand names of Helicoilļ¾® or Recoilļ¾®, helically-coiled wire thread inserts are a thread strengthening fastening device used to create high strength threads in softer core materials. The high performance internal thread provided by our wire inserts is far stronger than most parent materials, and is also heat, corrosion, and wear resistant too.
Our screw locking inserts have all of the advantages of a free running type plus the additional benefit of prevailing locking torque, which makes them a valuable and reliable choice for use in applications subject to cyclic vibration or impact.
The locking torque is achieved by the action of a polygonal grip coil in the insert that exerts radial pressure on the male thread, with each grip coil consisting of a number of tangential locking chords that protrude inside the minor diameter of the normal free running coils. As the male thread passes through these grip coils, the locking flats are displaced, thereby exerting radial pressure and prevailing locking torque on the male thread.
On removal of the male thread, the locking coil relaxes to its original form, allowing for repeated assembly whilst retaining a measurable level of prevailing torque.
Note: It is recommended that only close fit plated or lubricated bolts and screws are used with screw locking inserts. Pre-wind tools must be used to install locking inserts.
