🔩 M1.6–M6 Hex Socket Countersunk Screws – A2 Stainless Steel, Fully Threaded (3–40mm Overall Length)
You’re building a 3D printer, assembling a drone, or securing a delicate electronic panel – and you need screws that sit flush and won’t rust. These M1.6 to M6 hex socket countersunk screws are made from A2 stainless steel (304), giving you excellent corrosion resistance and high strength. The flat 90° head sinks flush into a pre‑drilled countersink, leaving a smooth, snag‑free surface. The hex socket (Allen) drive allows high torque without slipping – perfect for power tools. Available in diameters M1.6, M2, M3, M4, M5, and M6, with overall lengths from 3mm to 40mm (including head). Fully threaded. Ideal for electronics, machinery, automotive, and furniture where a flush finish and corrosion resistance are critical.
✨ Key Features – Hex Socket Countersunk Machine Screws
- 🔘 Countersunk flat head (90°) – Sits flush with the surface after proper countersinking. Smooth, professional finish.
- 🔧 Hex socket (Allen) drive – Allows high torque without cam‑out. Clean recess works with hex keys or power tools.
- 🛡️ A2 stainless steel (304) – Excellent corrosion resistance, oxidation resistance, and heat resistance. High strength and toughness.
- 📏 Wide metric range M1.6, M2, M3, M4, M5, M6 – Covers miniature electronics to light machinery.
- 📐 Overall lengths 3–40mm (including head) – Example: M4 x 10mm means total length from top of head to tip is 10mm. Fully threaded.
- ⚙️ Precision hex socket – Standard metric hex sizes for easy tool selection (see table below).
- 🔧 Widely used – Electronics (laptop casings), mechanical equipment (motor covers), automotive (ECU boxes), and furniture (hinges).
📏 Specifications – M1.6 to M6 Countersunk Hex Screws (A2 Stainless)
| Thread Diameter (M) |
Thread Pitch (mm) |
Overall Length Range (mm) * |
Hex Socket Size (mm) |
Head Style |
Material |
| 📐 Length measured from top of head to tip (total screw length). Fully threaded. Select exact size from dropdown. |
| M1.6 |
0.35 |
3, 4, 5, 6, 8, 10, 12, 14, 16, 20, 22, 25, 30, 35, 40
(exact availability varies) |
1.3 mm |
Countersunk / flat (90°) |
A2 304 Stainless |
| M2 |
0.4 |
1.5 mm |
| M3 |
0.5 |
2.0 mm |
| M4 |
0.7 |
2.5 mm |
| M5 |
0.8 |
3.0 mm |
| M6 |
1.0 |
4.0 mm |
* Lengths are typical – exact availability may vary. Please allow minor manual measurement errors. Hex socket sizes are approximate; always check fit with quality hex key.
📋 Why Choose Hex Socket Countersunk Screws?
| Benefit |
Description |
| Flush finish |
Countersunk head sits completely flush – ideal for sliding mechanisms, covers, and electronics where snag‑free surfaces are needed. |
| High torque capability |
Hex socket drive allows much higher torque than Phillips or slotted drives – perfect for power tools. |
| Corrosion resistant |
A2 stainless steel (304) resists rust in humid, outdoor, and coastal environments. |
| Fully threaded |
Maximum thread engagement ensures secure fastening in blind holes or when using nuts. |
❓ Frequently Asked Questions – Hex Socket Countersunk Screws
1. How do I measure the length of a countersunk hex screw?
For countersunk screws, the length is measured overall – from the top of the head to the tip. So an “M4 x 10mm” screw has a total length of 10mm including the head. All our lengths follow this standard.
2. Do I need to countersink the hole for these screws to sit flush?
Yes – these are true 90° countersunk screws. For a flush finish, drill a matching 90° countersink hole. Use a countersink bit slightly larger than the head diameter.
3. Are these screws fully threaded? What about longer lengths like 40mm?
Yes – all screws in this range (M1.6 to M6, up to 40mm) are fully threaded from under the head to the tip, giving you maximum grip in blind holes or through‑nut applications.
4. Can I use these screws outdoors? Will they rust?
A2 stainless steel (304) is highly corrosion‑resistant and suitable for outdoor use in most environments – rain, humidity, and coastal areas. For continuous saltwater immersion, choose A4 (316) stainless, but for general outdoor machinery and furniture, A2 is excellent.
5. What hex key size do I need for each screw?
Refer to the table above: M1.6 uses 1.3mm, M2 uses 1.5mm, M3 uses 2mm, M4 uses 2.5mm, M5 uses 3mm, M6 uses 4mm. Always use a quality hex key that fits snugly.
6. Do you offer other sizes like M8 or M10?
This listing covers M1.6 to M6. We also carry larger sizes in our store – please check other listings or contact us for custom orders.
