CoilSert Screw-Locking Metric Coarse M8×1.25 × 3D
CoilSert screw-locking wire thread insert, metric coarse M8×1.25, length 3D, precision-wound from 304 stainless steel diamond-section wire; the coil expands elastically to anchor itself after installation—no staking required. Provides continuous self-locking torque and resists vibration loosening. Volume pricing is negotiable.
| Part No. | 4184-8CN240 |
|---|---|
| Features | Self-locking, anti-loosening |
| Thread Size | M8×1.25 |
| Thread System | Metric coarse |
| Length | 3D |
| Material | 304 stainless steel |
| Finish | Plain (cadmium / silver / dry-film lubricant optional) |
Overview
The metric screw-locking CoilSert combines a standard diamond-section coil with a polygonal locking turn at the top. The locking turn presses on the screw flanks and generates a prevailing torque, so the joint resists vibration without threadlocker. Free-running behaviour is retained everywhere except the locking zone, so installation and removal stay predictable. This listing: thread M8×1.25, thread system Metric coarse, length 3D, material 304 stainless steel, finish Plain (cadmium.
Advantages
The locking turn sits in the entry threads, so resistance starts as soon as the screw engages and remains through the full travel, which is what prevents back-out under sustained vibration.
Because the coil is stainless, the locking force is not affected by plating build-up or corrosion product on the parent material.
Dimensions and load capacity match the free-running metric insert, so the locking version can replace it without changing the hole or the screw.
Prevailing torque is generated mechanically rather than chemically, so performance does not depend on surface cleanliness, cure time or shelf life of an adhesive.
Applications
Metric joints on vibrating machinery, serviceable panels that are opened repeatedly, pump and compressor mounts, and assemblies where a threadlocking fluid would contaminate a clean circuit or an optical path.
Specify the prevailing torque band together with the thread size. Over-tightening a screw into an oversized locking coil work-hardens the wire and permanently reduces the locking force, so a torque-controlled driver is preferable to hand assembly.
Product information is supplied by Toprecision. Custom parts can be produced to drawing — contact us for samples or a quotation.
Specifications across this series
219 parts in this series
Values are taken from each part’s own attribute set. Changing length, material or finish changes pull-out strength and installation torque, so compare the row that matches your drawing.
Selection and test data: engagement length, standards, salt-spray hours
FAQ
What are the key dimensions of this part?
Part No. 4184-8CN240, Features Self-locking, anti-loosening, Thread Size M8×1.25, Thread System Metric coarse.
What material and finish is it supplied in?
304 stainless steel; Plain (cadmium / silver / dry-film lubricant optional).
What should I verify before ordering or installing it?
Specify the prevailing torque band together with the thread size. Over-tightening a screw into an oversized locking coil work-hardens the wire and permanently reduces the locking force, so a torque-controlled driver is preferable to hand assembly.