Measure the total stack thickness of the materials you are clamping, then add the depth of the T-slot channel (typically 5–10 mm depending on the extrusion profile). Choose a bolt length that allows the nut to engage at least 1× the bolt diameter beyond the clamped material. For example, clamping 20 mm of material in a channel with 8 mm depth generally calls for a bolt around 30–35 mm long. When in doubt, size up — a slightly longer bolt with a washer is easier to work with than one that's too short.

Grade 8.8 is an ISO metric property class. The first digit (8) indicates a minimum tensile strength of 800 MPa; the second digit (8) indicates the yield-to-tensile ratio, giving a minimum yield strength of 640 MPa. In practice, these bolts are generally suitable for structural clamping, jig building, machine assembly, and moderate-load connections. They are not typically rated for safety-critical applications such as lifting equipment without additional engineering review.

These bolts are typically zinc-plated carbon steel, which provides basic corrosion resistance suitable for indoor workshops and sheltered environments. For prolonged outdoor exposure, high-humidity conditions, or contact with corrosive chemicals, we recommend applying a corrosion-inhibiting coating or contacting us to confirm available material options. In most cases, stainless steel alternatives would be more appropriate for fully outdoor use.

These bolts are designed for standard metric T-slot aluminum extrusions — commonly 20-series (20×20, 20×40), 30-series, and 40-series profiles — as well as T-track woodworking jig systems. The thread standard is metric coarse (ISO 68-1), compatible with standard drop-in T-slot nuts and hex nuts. Always verify the slot width of your specific extrusion against the bolt head dimensions before ordering, as slot widths can vary between manufacturers even within the same series.

Divide the mm value by 25.4 to get the decimal inch equivalent. Common conversions for this product range:

• 16mm ≈ 5/8"
• 25mm ≈ 1"
• 50mm ≈ 2"
• 100mm ≈ 3-15/16"
• 150mm ≈ 5-29/32"
• 200mm ≈ 7-7/8"
• 300mm ≈ 11-13/16"
• 500mm ≈ 19-11/16"

Match the bolt diameter to the T-slot channel width and the thread specification of your nut or insert. As a general guide: M6 and M8 are typically used in light-duty jigs, small extrusion profiles, and woodworking T-tracks; M10 and M12 suit medium structural assemblies and standard machine tool tables; M14 through M20 are generally chosen for heavy-duty clamping, large extrusion frames, and structural steel connections. Always cross-reference with your extrusion manufacturer's specifications.

Pack sizes vary by size and length to balance shipping weight and value. Smaller sizes (M6 up to 70mm, M8 up to 80mm) are available in 10-piece packs; mid-range sizes come in 5-piece packs; larger sizes (M10 110mm+, M12 100mm+, M14–M18 longer lengths, M16 160mm+, and all M20 sizes) are sold in 2-piece or 1-piece packs. Select your preferred quantity using the Amount (Pcs) option above — the available pack sizes will update based on your selected bolt size and length.