KNURLED THUMB SCREW STAINLESS STEEL FLAT HEAD GRIP KNOB SCREWS Ø 2.5 3 4 5 6 MM

Match the thread size (M2, M2.5, M3, M4, M5, or M6) to your existing threaded insert, nut, or tapped hole. For length, measure the depth of the threaded engagement you need — the shank should be long enough to achieve full thread engagement (typically 1–1.5× the thread diameter minimum) without bottoming out. For panel fastening, shorter lengths (3–10 mm) are common; for structural assemblies, 12–40 mm lengths provide more holding depth.

Stainless steel thumb screws are suitable for light-to-medium clamping loads such as panel retention, enclosure covers, and access doors. They are not intended for high-torque structural joints where a hex or socket head cap screw would be appropriate. For PC case panels, 3D printer enclosures, and aluminum extrusion frames, the holding strength is more than adequate when used with matching threaded inserts or nuts.

Stainless steel provides good corrosion resistance in typical indoor workshop and electronics environments. The alloy forms a passive oxide layer that resists rust under normal conditions. For outdoor or high-humidity applications, ensure the mating hardware is also corrosion-resistant to avoid galvanic issues. Periodic wiping with a dry cloth is sufficient maintenance for most use cases.

Yes — M3, M4, M5, and M6 sizes are the most commonly used thread sizes in 2020, 3030, and 4040 aluminum extrusion systems. Pair with T-slot nuts or threaded inserts rated for your extrusion profile. The flat head profile seats cleanly against extrusion faces without requiring a countersink.

Yes — M3 x 6 mm and M3 x 8 mm are the most common sizes for PC case side panels and drive bay covers. Verify your case uses M3 threads (most ATX and mATX cases do) before ordering. The knurled grip makes panel removal and reinstallation faster than standard slotted thumbscrews.

Single pieces (1 Pcs) are ideal for replacing a lost or damaged screw. Small packs (4–10 Pcs) suit single-project builds. Medium packs (22–38 Pcs) work well for full enclosure or frame builds where multiple access points need fastening. Large packs (50–80 Pcs) are suited for workshop stock, small-batch production, or multi-unit builds where consistent hardware across assemblies matters.

Thread form follows standard ISO metric tolerances. For precise fit confirmation in tight-tolerance applications, we recommend testing with a single piece before ordering bulk quantities. If you have specific tolerance requirements (e.g., 6g thread class), contact us to confirm before ordering.