KM02 Permanent One-Way Security Nuts
Permanent tamper-resistant security nuts with the same rounded indentation-pattern head as the KM01 but no removal path — tightened once with the restricted driver, then left. High torque, vibration-retightenable, M5–M12.
Last updated: 2026-11
Specifications
The KM02 is the one-way member of the KM security-nut family: the same rounded, indented head that defeats standard tools, driven only by the restricted matching driver — but as a permanent fixing it is not intended to be removed once installed. In the collected source the permanent driver both installs and allows retightening if vibration loosens the joint, yet the fixing itself stays in place for its service life. The collected stock table mirrors the KM01 exactly: M5 to M12, with head diameters from 12.1 mm to 24.2 mm and each size in zinc-plated case-hardened steel, Geomet-coated steel or A2 stainless steel. The case-hardened version again adds saw-and-chisel resistance and higher torque capacity. Typical settings are the permanent versions of the KM01's haunts: security fencing, street furniture, public transport and playgrounds. If the panel needs periodic access, quote the removable KM01 instead.
| Designation | KM02 — permanent one-way security nut, rounded head with indentation drive pattern |
|---|---|
| Size range | M5, M6, M8, M10, M12 (collected stock table) |
| Head diameter dk max, mm | M5: 12.1 · M6: 12.1 · M8: 16.1 · M10: 20.1 · M12: 24.2 |
| Head height k, mm | M5: 5.6 · M6: 5.6 · M8: 7.3 · M10: 9.2 · M12: 10.6 |
| Security principle | Installs with the restricted-supply matching driver; permanent one-way fixing — no removal path |
| Vibration behaviour | Can be retightened with the driver if vibration loosens the joint |
| Materials / finishes | Zinc-plated case-hardened steel (BZP); Geomet-coated steel; A2 stainless steel — all three offered in every tabulated size |
Materials
- Zinc-plated case-hardened steel (BZP)
- Geomet-coated steel
- Stainless steel A2
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (KM02 Permanent One-Way Security Nuts) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
Permanent but retightenable — how do both work together?
The permanent claim is about removal, not adjustment. The restricted driver engages the indentation pattern so an authorised crew can re-torque the nut if vibration backs it off, but the fixing has no practical removal path: with the driver restricted and no external grip surfaces, there is no public way to unscrew it. That makes the KM02 the option for joints you may need to service but never to dismantle.
KM02 or a shear nut — which permanent option?
A shear (breakaway) nut achieves permanence by destroying its own drive hex at installation — cheap and effective, but the leftover cone exposes an unplated surface and the installed torque is capped by the break-off. The KM02 keeps full high-torque capability, leaves no unplated surface exposed, and stays retightenable. Where those properties matter — high-torque permanent fixings, coated or stainless finishes — the KM02 is the stronger permanent choice; where lowest cost dominates and torque demands are modest, a shear nut does the job.
What is the MOQ and lead time for this nut type?
The minimum order quantity is 10,000 pieces. Stock items ship in 3–7 days; non-stock items are confirmed at quotation. Common diameters in this nut type are widely stocked; confirm the exact schedule against quantity and size mix at quotation.
What should an RFQ for this nut type state?
State the standard designation (for example DIN 985 or DIN 6923), nominal thread size and pitch (metric coarse unless fine pitch is required), material and strength pairing with the mating bolt, finish (plain, zinc, or hot-dip galvanized where compatible), required certificates such as a mill test report per EN 10204 3.1, and quantity per size — plus destination country.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support