6#-32 M3 M3.5 M4 Knurled Thumb Screws Aluminum + Stainless Thumbscrew Bolt Silve

Match the thread diameter to the tapped hole or threaded insert already in your panel or frame. M3 is common in small electronics enclosures and 3D printer frames; M4 is standard in aluminum extrusion T-slot systems and PC cases; M3.5 appears in some laptop and server chassis; UNC 6#-32 is the imperial equivalent used in many North American PC cases and rack equipment. If you're unsure, measure the existing screw with a thread gauge or caliper before ordering.

The thread length should be at least equal to your panel thickness plus the depth of the receiving threaded hole or nut. For thin sheet metal panels (typically 1–2mm), a 4–6mm thread length is usually sufficient. For thicker extrusion brackets or stacked panels, choose 10mm or longer. When in doubt, go slightly longer — you can always use a washer to take up slack, but a thread that's too short won't engage securely.

The aluminum variant (6061 alloy) is lighter and easier to turn by hand, making it ideal for weight-sensitive builds like PC cases, camera rigs, and portable enclosures. The stainless steel variant offers significantly higher tensile strength and corrosion resistance, making it the better choice for outdoor enclosures, humid environments, or applications where the screw will be tightened and loosened frequently over a long service life. Both finish in silver.

These thumb screws are designed for panel retention and access-cover fastening — applications where moderate clamping force is needed and hand-tightening is sufficient. They are not rated for high-torque structural joints or dynamic load-bearing connections. For structural applications requiring specific torque values, contact us to confirm material grade and tensile specifications before ordering.

The stainless steel variants offer good corrosion resistance for most indoor-humid and light outdoor applications. The anodized aluminum variants resist surface oxidation well in dry to moderately humid conditions, but anodizing can degrade with prolonged exposure to salt spray or harsh chemicals. For marine or outdoor-exposed installations, the stainless steel option is the more durable choice.

Yes — M3 and M4 thread diameters are the most common sizes used with 2020 and 3030 aluminum extrusion T-slot profiles. You will typically pair these thumb screws with a T-nut inserted into the extrusion channel. Select the thread length based on the T-nut engagement depth plus any panel or bracket thickness you're clamping. M3.5 and UNC 6#-32 are less common in extrusion systems but work with appropriately tapped brackets.

Each variant is sold as 1 piece per order (1 pc). This lets you select exactly the thread diameter and length combination you need without paying for sizes you won't use. If you need larger quantities, simply increase the order quantity at checkout or contact us for bulk pricing options.