M3 M4 Aluminum Knurled Thumb Screws with/without Spring Buffer — Shock Absorber Bolts

Match the thread size to your existing threaded hole or nut. M3 has a 3mm thread diameter and is typically used in PC cases, electronics enclosures, and lightweight panels. M4 has a 4mm thread diameter and is generally used in heavier-duty applications such as aluminum extrusion frames and industrial enclosures. When in doubt, measure the inner diameter of your threaded hole with a caliper before ordering.

The With Spring variant includes an integrated spring buffer that acts as a shock absorber, keeping the screw under constant tension and preventing it from loosening due to vibration. This is ideal for applications with movement or vibration — such as PC cooling fans, server racks, or mobile equipment panels. The Without Spring variant is a standard knurled thumb screw for static, hand-tightened fastening where vibration is not a concern.

Both M3 and M4 variants share an overall length of 26.5mm (≈1.04"). This measurement typically includes the knurled head and the threaded shank. The usable thread engagement length may vary — please confirm with your panel thickness before ordering, or contact us to confirm.

These screws are made from aluminum alloy, which is generally suitable for light-to-medium clamping and panel-fastening tasks. They are not typically recommended for structural load-bearing or high-torque applications. For heavy-duty fastening requiring greater tensile strength, a steel thumb screw would generally be more appropriate.

Aluminum naturally forms a thin oxide layer that provides moderate corrosion resistance, making these screws generally suitable for dry indoor environments and light outdoor use. The anodized finish adds an additional layer of surface protection. For prolonged exposure to moisture, salt air, or harsh chemicals, an anodized aluminum or stainless steel fastener would typically offer better long-term protection.

These are metric thread screws (M3 and M4), following the ISO metric thread standard. They are not compatible with imperial (UNC/UNF) threaded holes. Ensure your panel, enclosure, or nut uses metric threads before purchasing.

No — the color is an anodized finish applied to the aluminum surface. All color variants share the same material, dimensions, and mechanical properties. The anodized finish also adds a thin layer of surface protection in addition to the aesthetic benefit, making it a practical choice for color-matched PC builds and enclosure projects.

Yes. The knurled head is specifically designed for tool-free, hand-tightening. The textured grip pattern allows you to apply sufficient torque by hand for panel fastening, enclosure assembly, and similar light-duty tasks — no screwdriver or wrench required.