Knurled Thumb Screws M3 M3.5 Anodized Aluminum — Color Hand Grip Knob Bolts

Measure the total thickness of the material you need to clamp or fasten, then add 2–3mm for thread engagement. For example, a 5mm panel typically works well with an M3×7mm or M3×10mm screw. Available lengths range from 5mm (≈3/16") to 20mm (≈25/32"). When in doubt, size up — a slightly longer screw with a nut or threaded insert generally gives more secure engagement than one that's too short.

These are designed for hand-tightened, tool-free applications. They generally handle light-to-moderate clamping loads suitable for panels, covers, and enclosures. For high-torque or structural load-bearing joints, a standard hex bolt is typically recommended. In most cases, the limiting factor is the tapped hole or nut material rather than the screw itself.

The anodized finish provides a layer of corrosion resistance compared to bare aluminum. For occasional outdoor or mildly humid use they generally perform well. Prolonged exposure to salt spray, standing water, or harsh chemicals is not recommended without additional protection. For fully weatherproof applications, stainless steel thumb screws are typically a better fit.

These are metric threads (M3 and M3.5) following ISO coarse pitch standards. M3 is typically 0.5mm pitch and M3.5 is typically 0.6mm pitch. They are not compatible with UNC or UNF imperial threads. If your project uses #4-40 or #6-32 screws, these will not fit.

Anodizing is an electrochemical surface treatment that penetrates the aluminum rather than sitting on top like paint. Under normal hand-tightening use it is generally durable and resistant to chipping. Heavy abrasion, sharp tools, or prolonged contact with strong acids or alkalis can gradually affect the finish over time.

Yes — M3 knurled thumb screws are a popular choice for PC case side panels, top covers, and fan grilles, as well as RC car body posts and drone frame assembly where tool-free access is needed frequently. The 10 color options also allow for aesthetic customization or color-coding of different panel zones.

Pack sizes vary by size and color: 2-piece, 5-piece, 10-piece, and 25-piece packs are available. Select your preferred quantity from the Pack Quantity(Pcs) option above before adding to cart.

In most cases, yes. Standard M3 hex nuts, nylon lock nuts, and M3 threaded inserts (heat-set or press-fit) are generally compatible with M3 coarse pitch screws. For M3.5, confirm your nut or insert is rated for M3.5 — it is less common than M3 and M4, so verify before ordering in bulk.