What are Countersunk Rivets?
Countersunk rivets are blind rivets with a tapered head that seats in a countersunk hole. After setting, the head is flush with the surface for a clean finish and to avoid interference with sliding parts or covers. Most countersunk blind rivets use a 120° head angle.
When should I use countersunk rivets?
- Panels that need a flat surface for appearance or airflow
- Tracks, rollers, or sliding components where a protruding head could snag
- Enclosures and covers that must sit flush
How do countersunk blind rivets work?
Insert the rivet into a correctly sized countersunk hole. The tool pulls the mandrel to flare the body on the blind side and clamp the stack. The mandrel snaps at a designed point, leaving a durable, one-side installation and a flush head.
How to choose the right size
- Grip range: Match the rated range to the total material stack thickness.
- Diameter and hole size: Use the recommended drill size for the series. Keep the hole just over body diameter and deburr both sides.
- Materials: Aluminum for low weight, steel for economy strength, stainless for corrosion resistance. Consider galvanic compatibility with the joined metals.
What drill size for 1/8 in and 3/16 in countersunk rivets?
Use the chart below for common pairings, then confirm the exact drill in the datasheet for your series.
| Nominal rivet diameter | Recommended hole size (in) | Common drill size |
|---|---|---|
| 3/32 in | 0.097 – 0.100 | #41 |
| 1/8 in | 0.129 – 0.133 | #30 |
| 5/32 in | 0.160 – 0.164 | #20 |
| 3/16 in | 0.192 – 0.196 | #11 |
| 1/4 in | 0.257 – 0.261 | Letter F |
Notes: Drill and deburr square to the surface for best seating. Some specialty countersunk blind rivets are designed to sit nearly flush on both sides.
Common sizes, materials and finishes
- Popular diameters: 1/8, 5/32, 3/16, 1/4 in
- Head angle: typically 120° for blind rivets
- Bodies and mandrels: aluminum, steel, stainless
Installation and best practices
- Measure the total stack and select a rivet whose grip range covers it.
- Use the correct countersink and drill size. Deburr both sides to seat the head fully.
- Support the joint during pulling to limit pillowing, pull until the mandrel snaps.
- For sealing needs, use closed end styles in the relevant category or add a compatible sealant.
Common issues and quick fixes
- Head not fully flush, countersink angle or depth does not match, re-countersink and ensure correct drill size and deburring.
- Rivet spins in the hole, hole is oversized, step up diameter or verify proper countersink.
- Loose joint, stack outside grip range, re-select size or series.
Why buy Countersunk Rivets from AlbanyCountyFasteners.com
- Flush-head blind rivets in popular diameters and materials
- Options across open end, closed end, and structural styles
- Fast shipping, bulk pricing, and contractor-friendly pack sizes
- USA-based support for drill sizes, countersink angles, and installation tips
FAQs
Quick answers to high-intent questions about selecting and installing countersunk blind rivets.
What angle are countersunk blind rivets?
Most countersunk blind rivets use a 120° head angle. Match your countersink to that angle for a flush finish.
What drill size should I use for 1/8 in and 3/16 in?
Use #30 for many 1/8 in series and #11 for many 3/16 in series. See the table above and confirm for your exact part.
Where should I use countersunk rivets instead of dome head?
Use countersunk where a protruding head could snag or spoil the finish, for example panels, covers, tracks, and sliding hardware.
Do countersunk blind rivets come in closed end versions?
Yes. Closed end versions help block liquids and air through the rivet body. Select them when sealing is required.
Can countersunk rivets sit flush on both sides?
Some specialty designs minimize blind-side protrusion. Standard countersunk heads are flush on the visible side when used with a matching countersink.