Stainless Steel Thumb Screws M2–M8 | A2 Knurled Head Thumbscrews

Measure the total thickness of the material(s) you need to clamp or fasten, then add 1–2 thread diameters for adequate engagement. For example, if clamping 8mm of material with an M4 screw, a 10–12mm length is typically sufficient. Lengths in this listing range from 4mm (≈5/32") to 40mm (≈1-9/16").

A2 (304) stainless steel generally offers a tensile strength of around 500–700 MPa. These screws are well-suited for light-to-medium clamping, panel fastening, and adjustment tasks. For heavy structural or high-vibration loads, a hex-head bolt with a locking nut is typically recommended.

A2 stainless steel provides good corrosion resistance and is generally suitable for outdoor use in most environments. For highly corrosive, coastal, or marine environments, A4 (316) stainless steel is typically the better choice.

Yes. These thumb screws use standard ISO metric coarse threads (M2, M2.5, M3, M4, M5, M6, M8). They are compatible with any metric-threaded nut, brass heat-set insert, or tapped hole of the matching size — no special hardware required.

Yes. M3 and M4 sizes are commonly used in 3D printer frames, extruder assemblies, and electronics enclosures. M2 and M2.5 are popular for small PCB standoffs and camera mounts. Always verify the thread size and length against your specific application before ordering.

No — the knurled head is designed for finger-tightening without any tools. For applications requiring slightly higher torque, a coin or flat-head screwdriver can typically be used along the knurled rim for additional leverage.

M4 or M5 are the most common choices for panel fastening on enclosures and equipment covers. Choose a length that passes through the panel thickness with at least 5–6mm of thread engagement into the receiving nut or insert for a secure hold.