🔧 Product Overview: M3 x 50mm Anodized Aluminum Knurled Thumb Screws – Hand Grip Knob Bolts
For applications requiring a long reach and tool‑less fastening, these M3 x 50mm knurled thumb screws are an excellent choice. Machined from 6061 aluminum alloy with a durable anodized finish, they feature a round, diamond‑knurled head that provides a secure non‑slip grip for hand tightening and loosening – no screwdriver needed. The 50mm thread length (measured under the head) is ideal for thicker panels, through‑hole assemblies, or applications where extra thread engagement is required. Fully threaded with M3 coarse pitch (0.5mm). Available in a variety of vibrant anodized colors to add style to your project. Perfect for machinery, precision molds, bearing assembly, 3D printers, and custom fixtures.
✨ Why This Long‑Reach Knurled Thumb Screw Is a Workshop Essential
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Long 50mm thread length – Ideal for thick panels, deep tapped holes, or when you need extra thread engagement for secure fastening.
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High‑quality 6061 aluminum alloy – Lightweight, strong, and corrosion‑resistant. Anodized finish adds durability and a professional appearance.
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Knurled round head for tool‑less grip – Diamond knurl pattern provides excellent finger traction for hand tightening and loosening – no tools required.
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M3 metric thread – fully threaded – Standard coarse pitch (0.5mm). Threads run the entire 50mm length for maximum grip and compatibility with M3 nuts.
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Smooth, burr‑free workmanship – Neat threads, even force distribution, and high‑quality materials ensure anti‑corrosion and long service life.
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Vibrant anodized colors – Add style and uniqueness to your project with a variety of color options (select from dropdown).
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Wide applications – Machinery, precision molds, bearing assembly, 3D printers, camera rigs, jigs, and fixtures.
📏 Technical Specifications – M3 x 50mm Knurled Thumb Screw
| Specification |
Details |
| Product Type |
Knurled Thumb Screws (Hand Grip Knob Bolts) |
| Material |
6061 Aluminum Alloy (anodized) |
| Thread Pitch |
0.5mm (metric coarse) |
| Thread Size |
M3 |
| Thread Length (under head) |
50mm |
| Length Measurement |
Under head – from underside of head to tip (head not included) |
| Head Style |
Round knurled head (diamond knurl) |
| Drive Style |
Hand grip (toolless) |
| Finish |
Anodized (multiple colors available) |
| Tolerance |
±0.2mm |
❓ FAQs – M3 x 50mm Knurled Thumb Screws
🔸 What is the typical use for a 50mm long thumb screw?
This long thread length is ideal for applications where you need to fasten through thick panels (e.g., 30–45mm thick), or when using a nut on the back side with extra thread engagement. It is also useful for jigs, fixtures, and custom machinery where a long reach is required.
🔸 How is the 50mm thread length measured? Is it the total length?
Thread length is measured from the underside of the knurled head to the tip of the thread. The head itself is not included. The total length (including the head) is approximately 55–60mm depending on head height.
🔸 Is this screw fully threaded? What is the thread pitch?
Yes – it is fully threaded from under the head to the tip. The thread pitch is standard M3 coarse: 0.5mm.
🔸 Will the anodized color fade or wear off?
Anodizing is an electrochemical process that bonds the color to the aluminum surface. It is durable and will not peel like paint. Under normal hand use, the color will remain vibrant for years. Heavy abrasion may wear the finish, but typical thumb screw applications are gentle.
🔸 Can I use this screw with a nut, or is it for tapped holes only?
It is a standard machine screw – it works with matching M3 nuts or in pre‑tapped holes. For through‑hole applications, use a nut on the back side. The 50mm length gives you plenty of thread for nut engagement.
🔸 Are these screws magnetic? Will they affect sensitive electronics?
Aluminum is non‑magnetic, so this thumb screw will not interfere with sensitive electronics, hard drives, or magnetic sensors. It is completely safe for use near precision equipment.
