Aluminum +Stainless Steel Knurled Thumb Screws 6#-32 M3 M3.5 M4 Bolts Sky blue

Match the thread diameter to your tapped hole or threaded insert. UNC 6#-32 is the standard for most North American PC cases and electronics enclosures. M3 is the most common metric size for 3D printer frames and small electronics. M3.5 fits certain European PC motherboard standoffs. M4 is used in heavier aluminum extrusion assemblies and larger enclosures. When in doubt, check your existing hardware with a thread gauge or compare against a known fastener.

Thread length should be at least equal to the panel thickness plus the depth of your tapped hole or nut. For thin sheet metal panels (typically 1–2 mm), a 4–6 mm thread length is usually sufficient. For thicker extrusion slots or stacked panels, choose 10 mm or longer. If you are threading into a captured nut or standoff, add the nut height to your panel thickness to determine the minimum thread engagement needed.

These thumb screws are designed for low-torque, tool-free applications such as access panels, side covers, and removable lids — not for high-load structural joints. The knurled head limits the torque that can be applied by hand, which is intentional for repeated removal. For structural connections that require a driver and defined torque, use a standard socket-head or hex-head fastener instead.

The sky blue finish is applied as an anodized or coated layer that provides corrosion resistance and color retention under normal indoor use. Like all colored fastener finishes, it can show wear at contact points after many removal cycles. For applications where appearance is critical long-term, avoid over-tightening and use a nylon washer between the head and the panel surface to reduce abrasion.

The stainless steel variants with surface treatment offer better corrosion resistance for damp or outdoor-adjacent environments. Aluminum variants are suitable for dry indoor use. Neither variant is rated for continuous submersion or direct outdoor weathering. For outdoor enclosures, consider adding a thread sealant and inspect fasteners periodically for surface oxidation.

Yes — the UNC 6#-32 variant is the standard thread used in the vast majority of ATX, mATX, and ITX PC cases for side panels, drive cages, and expansion slot covers. Select the 6#-32 thread diameter and a thread length appropriate for your panel thickness (typically 4–6 mm for standard steel panels). The M3 variant is compatible with some SFF cases and most 3D printer frame extrusions.

Aluminum alloy thumb screws are lighter and easier to anodize for consistent color, making them ideal for weight-sensitive builds like PC cases and portable enclosures. Stainless steel variants are heavier but offer higher tensile strength and better corrosion resistance, making them preferable for workshop fixtures, outdoor-adjacent enclosures, or applications where the fastener may be exposed to moisture or mild chemicals.