M8 Adjustable Knurled Thumb Shoulder Screws Aluminum Stainless Steel 6-100mm D20

Measure the total grip length — the combined thickness of all layers the screw must clamp — and add the thread engagement depth you need (typically 1.0–1.5× the thread diameter, so 8–12 mm for M8). Choose the next available length at or above that total. For example, clamping a 10 mm panel with 10 mm thread engagement requires at least 20 mm; select the M8 × 20 mm variant.

The shoulder (D20) is 20 mm in diameter. It acts as a bearing surface that distributes clamping force over a larger area than the thread alone, which reduces the risk of deforming thin panels or soft materials such as acrylic or thin aluminum sheet. Confirm your panel clearance hole or counterbore accommodates 20 mm before ordering.

These thumb screws are designed for hand-tightened, frequently accessed joints — enclosure covers, access panels, and adjustable fixtures — rather than high-torque structural connections. Aluminum alloy provides adequate strength for typical panel-retention loads. For joints requiring torque tools or rated structural performance, contact us to confirm suitability before ordering.

Anodizing creates an aluminum oxide layer that resists mild moisture and humidity. These screws are suitable for indoor and sheltered outdoor use. For prolonged direct exposure to rain, salt spray, or harsh chemicals, consider stainless steel alternatives or apply an additional sealant to the anodized surface.

Yes. The M8 × 1.25 mm thread is the standard metric coarse pitch and mates directly with M8 T-nuts, heat-set inserts, and tapped holes in aluminum, steel, or plastic. No adapters are required. Verify that the 20 mm shoulder clears any counterbore or panel opening in your design.

Color selection is typically functional or aesthetic. Use a single color for all fasteners on one assembly for a clean look, or assign different colors to different access zones (e.g., Jewel Blue for power sections, Burgundy Red for high-voltage areas) to create an intuitive visual system. All colors share identical mechanical specifications — color choice does not affect thread dimensions or load capacity.

Shorter lengths (6–12 mm) are suited for thin panel captures where the fastener engages a shallow tapped hole or insert — common in electronics enclosures and instrument panels. Longer lengths (50–100 mm) provide extended reach for thicker assemblies, spacer stacks, or applications where the screw must pass through multiple layers before engaging the thread. Select based on your total grip + engagement requirement.