UNC 1/4 - 20 Aluminum Knurled Flat Thumb Screws 5/8" (16mm) – Low - Profile Hand Grip Bolts - HomeDIYer
UNC 1/4 - 20 Aluminum Knurled Flat Thumb Screws 5/8" (16mm) – Low - Profile Hand Grip Bolts - HomeDIYer
UNC 1/4 - 20 Aluminum Knurled Flat Thumb Screws 5/8" (16mm) – Low - Profile Hand Grip Bolts - HomeDIYer
UNC 1/4 - 20 Aluminum Knurled Flat Thumb Screws 5/8" (16mm) – Low - Profile Hand Grip Bolts - HomeDIYer
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UNC 1/4 - 20 Aluminum Knurled Flat Thumb Screws 5/8" (16mm) – Low - Profile Hand Grip Bolts - HomeDIYerUNC 1/4 - 20 Aluminum Knurled Flat Thumb Screws 5/8" (16mm) – Low - Profile Hand Grip Bolts - HomeDIYerUNC 1/4 - 20 Aluminum Knurled Flat Thumb Screws 5/8" (16mm) – Low - Profile Hand Grip Bolts - HomeDIYerUNC 1/4 - 20 Aluminum Knurled Flat Thumb Screws 5/8" (16mm) – Low - Profile Hand Grip Bolts - HomeDIYer

UNC 1/4-20 Aluminum Knurled Flat Thumb Screws 5/8" (16mm) – Low-Profile Hand Grip Bolts

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Price:
$7.34 USD
Stock:
In stock (500 units), ready to be shipped

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Description

 

UNC 1/4-20 Flat Knurled Thumb Screws 5/8" (16mm) — Secure Hand-Tightened Fastening for Panels and Fixtures

When you need a tool-free fastener that actually holds — for enclosure panels, jig clamping plates, or access covers on thicker material stacks — a flat knurled thumb screw with enough thread engagement makes the difference between a secure fit and a loose connection. These UNC 1/4-20 flat thumb screws in 5/8" (16mm) length are designed for makers, woodworkers, electronics builders, and CNC fabricators who need a low-profile hand-grip bolt that works reliably across repeated tighten-and-release cycles.

Each screw features a UNC 1/4-20 thread (1/4" diameter, 20 threads per inch) machined from aluminum alloy with a flat, knurled head for tool-free hand tightening. The 5/8" (16mm) length provides more thread engagement than shorter variants, making it suitable for thicker panels and deeper tapped holes. Available in 10 anodized colors — Wine Red, Rose Red, Golden, Royal Blue, Sky Blue, Black, Silver, Green, Purple, and Orange — and in packs of 1, 3, 5, 10, 15, or 20 pieces. The single-piece option lets you test fit before ordering in bulk.

Typical use cases include woodworking jig clamping plates, electronics enclosure panel fastening with thicker walls, CNC fixture hold-downs requiring deeper thread engagement, 3D printer frame access panels, and router table insert plates — anywhere a low-profile 1/4-20 flat thumb screw needs to be hand-tightened and released repeatedly without tools.

🔩 Thread Compatibility: UNC (Unified National Coarse) 1/4-20 — fits any standard 1/4-20 nut, threaded insert, or tapped hole. Confirm your application uses UNC threading before ordering.

✅ Key Features of These 1/4-20 Flat Knurled Thumb Screws

  • 📏5/8" (16mm) Length for Deeper Thread Engagement — At 16mm, this flat thumb screw provides more thread engagement than shorter variants, making it a reliable choice for thicker panels, deeper tapped holes, and stacked-material jig fixtures where a 10mm screw would fall short.
  • ✋Knurled Flat Head for Tool-Free Operation — The knurled pattern on the flat head delivers enough grip for secure hand tightening and loosening without a screwdriver or wrench — practical for enclosure panels and jig fixtures that need frequent access.
  • 🔩UNC 1/4-20 Standard Thread — One of the most widely used thread standards in the US, compatible with standard nuts, threaded inserts, and tapped holes across woodworking, electronics, and fabrication applications.
  • ⚡Lightweight Aluminum Alloy Construction — Aluminum alloy keeps the fastener light without sacrificing the rigidity needed for hand-tightened clamping in jigs, enclosures, and DIY assemblies — a practical choice where weight matters.
  • 🎨10 Anodized Colors for Visual Identification — Color-code fasteners by zone, axis, or function across your build. All 10 colors share the same aluminum alloy material and 1/4-20 thread dimensions — color is finish only.
  • 📦Single-Piece to 20-Pack Options — Order 1 piece to test fit before committing, or choose packs of 3, 5, 10, 15, or 20 for multi-point builds and production runs. Larger packs offer a lower per-unit cost.

📐 Technical Specifications — UNC 1/4-20 Flat Knurled Thumb Screws

Thread Standard UNC (Unified National Coarse)
Thread Size 1/4-20 (1/4" diameter, 20 TPI)
Length 5/8" (16mm)
Head Style Flat knurled (low-profile)
Material Aluminum alloy
Finish / Color Anodized — Wine Red, Rose Red, Golden, Royal Blue, Sky Blue, Black, Silver, Green, Purple, Orange
Drive Method Hand-tightened (tool-free)
Quantity per Pack 1 / 3 / 5 / 10 / 15 / 20 pcs (see variant options)
Recommended Torque Hand torque only — not for high-load structural use
Corrosion Resistance Moderate (aluminum alloy); contact us to confirm for outdoor use
Country of Origin See variant options
⚠️ Length Selection Note: This listing is the 5/8" (16mm) version. If you need a shorter screw for thin panels or shallow tapped holes, see our 3/8" (10mm) listing. Contact us if you need a different length.

❓ Frequently Asked Questions

How do I know if 5/8" (16mm) is the right length for my application?

Measure the total thickness of the material stack you need to clamp or fasten — your panel, fixture plate, or insert. For a 1/4-20 screw, you generally want at least 3/8" of thread engagement in the receiving material. A 5/8" (16mm) screw is typically a good fit for panels or stacked materials in the 1/4" to 3/8" thickness range, leaving adequate thread engagement. If your stack is thinner, consider our 3/8" (10mm) version; if thicker, contact us to confirm availability of longer lengths.

How strong are aluminum flat thumb screws for clamping and panel fastening?

Aluminum alloy flat thumb screws are generally suited for light-to-medium hand-tightened clamping loads — enclosure panels, jig fixtures, access covers, and DIY assemblies. They are not intended for high-torque structural applications where steel fasteners are typically required. For repeated hand-tightening cycles, aluminum alloy generally holds up well in non-impact applications.

Can these flat thumb screws be used outdoors or in damp environments?

Aluminum alloy has natural corrosion resistance, making these screws generally suitable for light outdoor or humid-environment use. For prolonged salt-spray exposure or fully submerged conditions, stainless steel fasteners are typically recommended. Contact us to confirm suitability for your specific environment.

What thread standard do these use — will they fit standard nuts and threaded inserts?

These use UNC (Unified National Coarse) 1/4-20 threading — 1/4" diameter, 20 threads per inch. They are compatible with any standard UNC 1/4-20 nut, threaded insert, or tapped hole. This is one of the most widely used thread standards in the US, common in woodworking jigs, electronics enclosures, CNC fixtures, and general fabrication.

When should I choose the 5/8" (16mm) length over the 3/8" (10mm) version?

Choose the 5/8" (16mm) length when your panel or fixture stack is thicker — typically in the 1/4" to 3/8" range — and you need more thread engagement for a secure hold. The 3/8" (10mm) version is better suited for very thin panels or shallow tapped holes where a longer screw would bottom out or protrude. If you are unsure, measure your stack thickness and compare against the screw length.

Do the colors affect the material or thread dimensions?

No — all color variants are made from the same aluminum alloy material. The colors (Wine Red, Rose Red, Golden, Royal Blue, Sky Blue, Black, Silver, Green, Purple, Orange) are anodized or coated surface finishes. They do not affect thread dimensions or mechanical performance and are primarily used for visual identification or color-coding in multi-axis or multi-zone builds.

Can I order just one screw to test fit before buying a larger pack?

Yes — this listing is available in a 1-piece option, making it easy to test fit and confirm compatibility with your application before committing to a larger pack. Larger packs (3, 5, 10, 15, or 20 pieces) offer a lower per-unit cost for production or multi-point builds.

🛒 Select your color and quantity above, then add to cart — ships from our US warehouse.

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