M3*5/6/8/12/20/25/35/40/50mm Aluminum Alloy Bolts Knurled Flat Head Thumb Screws

Measure the thickness of the material being fastened plus any gap or nut depth. As a general rule, the shank should extend at least 3–4 full thread turns (1.5–2 mm for M3) beyond the panel into the nut or insert. For a 2 mm aluminum panel with a standard M3 hex nut, a 6–8 mm shank is typically sufficient. For thicker extrusion slots or stacked panels, choose 10–16 mm or longer.

These thumb screws are designed for panel access and light-duty retention — think side panels, covers, and access doors — rather than primary structural joints under sustained load or vibration. For high-vibration or load-bearing applications, use steel fasteners with thread-locking compound instead.

Anodizing is an electrochemical process that integrates color into the aluminum oxide layer rather than sitting on top as paint. Under normal indoor use — repeated hand-tightening and removal — the finish holds well. Abrasive tools or harsh chemicals can damage the layer, so hand-tighten only and avoid solvents on the head.

Yes. The M3×0.5 mm thread is the standard metric M3 pitch and is compatible with M3 hex nuts, nylon-insert lock nuts, brass heat-set inserts, and tapped holes in aluminum or steel panels. Always verify the insert or nut inner diameter is M3 before ordering.

The anodized finish provides moderate corrosion resistance suitable for typical indoor environments. For outdoor or high-humidity applications, aluminum can develop surface oxidation over time even with anodizing. If your build is exposed to moisture, consider applying a light coat of protective wax or choosing stainless steel fasteners instead.

The D10×5 head (5 mm tall) is available on shorter shanks (5, 6, 8 mm) and offers a lower-profile look. The D10×6 head (6 mm tall) is used on longer shanks (10–50 mm) and provides slightly more grip surface for longer tightening strokes. Both share the same 10 mm diameter, so they are interchangeable in terms of hole clearance.

Each variant is a specific color + length + quantity combination. To mix, add each combination as a separate line item to your cart. The 5-pack option is the most cost-effective way to stock a single color/length combination for a full panel build.