Flat Head Round Body Open-End Rivet Nuts
The baseline rivet nut configuration: flat (normal) head, round body, open end — set from one side into a plain round hole to leave a reusable load-bearing thread. Catalog coverage runs #4-40 to 1/2"-20 unified and M3 to M12, in steel, stainless, aluminum and other body materials. The default choice when installation torque is moderate and nothing has to be sealed.
Last updated: 2026-11
Specifications
Every rivet nut selection starts from this baseline: a round body that collapses in a plain drilled hole, a flat head that sits on the sheet surface, and an open end that leaves the thread accessible from the blind side. The collected manufacturer line positions the round body as the most versatile rivet nut design — it installs into a simple round hole and works across virtually any material, thickness, or application — and lists the smooth round body explicitly as the light-duty choice with minimal panel damage. That is the honest envelope for this configuration: where the screw it carries sees real torque, step up to a knurled or hex body; where the thread must be sealed, move to a closed end. What the flat-head round-body open-end form buys you is the cheapest hole preparation (no countersink, no hex form), the widest catalog coverage and the simplest installation on standard rivet-nut tooling — which is why it is the configuration distributors stock deepest.
| Type | Rivet nut — flat head, round body, open end; one-sided installation into a plain round hole, reusable internal thread |
|---|---|
| Round body positioning | Manufacturer line description: "the most versatile and widely used rivet nut design ... install into a simple round hole and work across virtually any material, thickness, or application" |
| Full-metric series availability | COLM (round smooth, large flange) · COKI (round smooth, small flange) — light-duty applications with minimal panel damage; knurled rounds CKLM/CKKM share the same body family |
| Thread size coverage (catalog facets) | Unified #4-40, 6-32, 8-32, 10-24, 10-32, 12-24, 1/4"-20, 1/4"-28, 5/16"-18, 5/16"-24, 3/8"-16, 3/8"-24, 1/2"-13, 1/2"-20; metric M3, M4, M5, M6, M8, M10, M12 |
| Body materials (catalog facets) | Aluminum, brass, copper, steel, stainless steel, plus nickel, plastic and Grade 2 titanium specialty lines |
| Set thickness windows (catalog facets) | For-material-thickness bands run from 0.010" to 0.06" up to 0" to 0.197" depending on body line — select so the set sheet sits inside the band |
| Torque selection caveat | No single torque value applies across sizes: spin-out depends on rivet nut material, thread size, body shape, sheet material and thickness, hole diameter, grip range, setting force and surface treatment — rate the joint from the selected product data |
| MOQ / lead time | 10,000–50,000 pieces by size; 10–20 days |
| Thread | Body diameter max (mm) | Head diameter (mm) | Hole in sheet (mm) | Grip range options (mm) | Min sheet (mm) |
|---|---|---|---|---|---|
| M3x0.5 | 4.98 | 7 | 5 | 0.5-2.0 / 2.0-3.5 | 0.5 |
| M4x0.7 | 5.98 | 9 | 6 | 0.5-2.5 / 2.5-4.5 | 0.5 |
| M5x0.8 | 6.98 | 10 | 7 | 0.5-3.0 / 3.0-5.5 / 5.5-8.0 | 0.5 |
| M6x1 | 8.98 | 13 | 9 | 0.5-3.0 / 3.0-5.5 / 5.5-8.0 | 0.5 |
| M8x1.25 | 10.98 | 16 | 11 | 0.5-3.0 / 3.0-5.5 / 5.5-8.0 | 0.5 |
| M10x1.5 | 12.98 | 19 | 13 | 0.7-3.5 / 3.5-6.0 / 6.0-9.0 | 0.7 |
| M12x1.75 | 15.98 | 23 | 16 | 1.0-4.0 / 4.0-7.0 | 1.0 |
Materials
- Steel
- Stainless steel
- Aluminum
- Brass
- Copper
- Specialty: nickel, plastic, Grade 2 titanium
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 (Flat Head Round Body Open-End Rivet 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 10,000–50,000 pieces depending on size. Standard production run 10–20 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
When is a plain round-body open-end rivet nut the right choice?
When the joint is ordinary: the screw carries moderate torque, the hole can stay plain, and nothing behind the thread needs sealing. The round body sets in a simple drilled hole in virtually any sheet material and thickness, and the flat head needs no countersink — the cheapest per-point installation in the rivet nut family. Two signals move you off this baseline: installation torque near the spin-out limit of a smooth body (go knurled or half/full hex), or a thread that must not admit fluid or dust from the blind side (go closed end).
What does "open end" change about the installed part?
The body is a through tube: after setting, the internal thread runs the full body and the blind side stays open. For most assemblies that is irrelevant — the sheet backs the thread and the far side is not a pressure or contamination boundary. It matters where dust, fluid or the blind-side environment could reach the screw through the insert; that is the case a closed-end rivet nut exists for. Open end is also the form with the deepest catalog coverage across thread sizes and materials, so availability is rarely a constraint.
What is the MOQ and lead time for these rivets?
Minimum order quantity is 10,000–50,000 pieces depending on size and material. Standard production lead time is 10–20 days. Common blind rivet sizes are widely stocked — confirm the exact schedule against quantity and size mix at quotation.
What should an RFQ for these rivets state?
State the rivet subtype (open-end, closed-end, structural blind rivet or rivet nut), body diameter, grip range or total material thickness, head style (dome, countersunk or large flange), body and mandrel materials (for example aluminum body with steel mandrel, or all-stainless), finish, 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