CL01 Clutch Head One Way Round Security Machine Screws
Round head one-way clutch head security machine screws, M3–M8 as tabulated: head diameters 6.0–13.0 mm, head heights 2.4–4.8 mm. Tabulated length availability runs 5–50 mm on M3/M4 and 8–70 mm on M5/M6/M8; installs with a standard slotted screwdriver, turns one way only.
Last updated: 2026-11
Specifications
CL01 is the machine-screw baseline of the clutch head one-way line: a round head on a slotted drive with chamfers at each side, so any standard slotted screwdriver drives the screw in — and slips out the moment torque is applied anti-clockwise. That asymmetry is the security: the fixing goes in with the most common tool on any site but cannot be backed out with it, making it a permanent one-way fixing for surfaces the public can reach. The collected tabulation runs M3 to M8 with head diameters from 6.0 mm to 13.0 mm and head heights from 2.4 mm to 4.8 mm, and it is the one page in this batch whose availability matrix carries legible orderable markings: M3 and M4 from 5 mm to 50 mm, M5 and M6 from 8 mm to 70 mm, M8 from 10 mm to 70 mm. The design is classed for medium-torque applications — the shallow slotted drive will not survive high torque the way a hex or Torx recess would — and the source notes installation can be time-consuming in volume, which is the accepted cost of a tooling-free one-way fixing. Typical ground named for this line: public facilities, transport interchanges and other areas where maintenance access is not needed but tamper resistance is.
| Designation | CL01 — round head security machine screw, clutch head one-way drive (slotted drive with side chamfers; turns clockwise only) |
|---|---|
| Thread range (tabulated) | M3, M4, M5, M6, M8 |
| Head diameter dk per thread (mm) | M3 6.0 · M4 7.4 · M5 9.3 · M6 10.2 · M8 13.0 |
| Head height k per thread (mm) | M3 2.4 · M4 2.8 · M5 3.2 · M6 3.5 · M8 4.8 |
| Length availability (as marked) | M3 and M4 marked available to order in 5–50 mm; M5 and M6 in 8–70 mm; M8 in 10–70 mm |
| Security principle | One-way permanent fixing — installs with a standard slotted screwdriver; the driver cams out under anti-clockwise torque, so ordinary tools cannot remove it |
| Torque class (source-stated) | Medium torque applications |
Materials
- Confirmed at quotation (collected page states no standard material line)
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 (CL01 Clutch Head One Way Round Security Machine Screws) 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
How is a one-way clutch head different from a pin-TX security screw?
Direction, not tooling. A pin-TX screw needs a special driver but works both ways, so it suits panels that get serviced. A clutch head screw needs no special tool at all going in — any slotted driver fits the slot — but the side chamfers make the driver slip out the instant you try to turn it backwards. It is the cheaper choice for permanent fixes in public space, at the price of being effectively irreversible without dedicated removal tooling.
Which lengths are orderable in which thread?
Exactly what the collected matrix marks: M3 and M4 from 5 mm to 50 mm, M5 and M6 from 8 mm to 70 mm, and M8 from 10 mm to 70 mm — the mark means available to order, not ex-stock. Shorter or longer combinations outside those bands are a quotation enquiry.
What is the MOQ and lead time for these security screws?
Minimum order quantity is 10,000 pieces per item. Stocked sizes ship in 3–7 days; sizes quoted as available to order, and non-standard sizes or materials, are quoted with a confirmed schedule. Confirm the exact schedule against quantity and size mix at quotation.
What should an RFQ for these security screws state?
State the designation code (CL01 through CL06) and head style, the drive (clutch head one-way — fitted with a standard slotted screwdriver), nominal thread size and length, material and finish, the substrate or mating part, required certificates, and quantity per size — plus destination country.
Related knowledge
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- Hex Bolts vs Socket Head Cap Screws: What the Evidence Settles on Strength, Clearance and Cost
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