Blue Zinc Phillips Countersunk Machine Screws — Flush Fit for Clean, Professional Assemblies
When a protruding screw head gets in the way of a clean finish, you need a flat head machine screw that sits perfectly flush. Whether you're a woodworker building cabinet frames, a maker assembling electronics enclosures, or a maintenance tech fastening metal brackets, these blue zinc plated Phillips countersunk machine screws deliver a reliable, flush-mount connection without the bulk.
Each pack contains machine screws in your selected size and quantity — M4, M5, or M6 diameter — with lengths ranging from 8mm (5/16") to 40mm (1‑9/16"). The screws are made from carbon steel with a blue zinc electroplated finish that provides a distinctive metallic-blue appearance and moderate corrosion resistance. Packing quantities are 200 pcs (M4), 100 pcs (M5), or 50 pcs (M6) depending on the size selected.
These flat head machine screws are well suited for furniture and cabinetry assembly where a flush surface is required, electronics and enclosure fabrication where panel-mount screws must not protrude, and light machinery and bracket fastening in workshops and production environments. The Phillips drive makes them compatible with standard power drivers for fast installation.
🔵 Compatibility: ISO metric coarse thread — M4 (0.7mm pitch), M5 (0.8mm pitch), M6 (1.0mm pitch). Fits standard metric nuts, threaded inserts, and tapped holes per ISO 68-1. Phillips PH2 driver recommended for M4/M5; PH2 or PH3 for M6.
✅ Key Features of These Blue Zinc Phillips Countersunk Machine Screws
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🔩Flush-Mount Flat Head Design — The countersunk head tapers to sit flush with or below the material surface, ideal for flat head machine screw applications in panels, brackets, and enclosures.
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🛡️Blue Zinc Electroplated Finish — The electroplating process bonds a zinc layer to the carbon steel base, offering moderate rust resistance for indoor and sheltered-use fasteners.
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⚙️Phillips Cross Drive — Compatible with standard PH2/PH3 bits and power drivers, reducing installation time on bulk fastening jobs like Phillips countersunk bolts for metal assemblies.
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📐Wide Size Range — Available in M4, M5, and M6 diameters with lengths from 8mm (5/16") to 40mm (1‑9/16"), covering most light-to-medium duty metric machine screw applications.
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📦Bulk Pack Value — Sold in packs of 50, 100, or 200 pieces depending on size, making these practical for production runs, workshop stock, and bulk machine screw restocking.
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🔧ISO Metric Thread Compatibility — Follows ISO 68-1 coarse thread standards, ensuring consistent fit with metric nuts, threaded inserts, and pre-tapped holes used in metric fastener assemblies.
📐 Technical Specifications — Phillips Flat Head Machine Screws
| Product Type |
Phillips Countersunk (Flat Head) Machine Screw |
| Drive Type |
Phillips (Cross) — PH2 / PH3 |
| Head Style |
Countersunk / Flat Head (flush-mount) |
| Material |
Carbon Steel |
| Surface Finish |
Blue Zinc Electroplated |
| Thread Standard |
ISO Metric Coarse (ISO 68-1) |
| Available Diameters |
M4, M5, M6 |
| Thread Pitch |
M4: 0.7mm | M5: 0.8mm | M6: 1.0mm |
| Available Lengths |
8mm (5/16") to 40mm (1‑9/16") — See variant options |
| Packing Quantity |
M4: 200 pcs | M5: 100 pcs | M6: 50 pcs |
| Strength Grade |
Contact us to confirm |
| Corrosion Resistance |
Moderate — suitable for indoor / sheltered use |
| Country of Origin |
Contact us to confirm |
⚠️ Heads up: Blue zinc plating is designed for indoor and light sheltered use. For outdoor, marine, or high-humidity environments, stainless steel fasteners are generally recommended. Contact us if you need corrosion-resistant alternatives.
❓ Frequently Asked Questions
How do I choose the right screw length for my project?
A general rule of thumb is that the screw should penetrate the base material by at least the diameter of the screw. For example, an M5 screw (5mm diameter) should typically embed at least 5mm into the receiving material. Available lengths in this listing range from 8mm (5/16") to 40mm (1‑9/16") — choose based on your combined material thickness plus the required thread engagement depth.
How strong are blue zinc plated machine screws?
These screws are generally manufactured from carbon steel with a blue zinc electroplating finish. Carbon steel machine screws typically meet property class 4.8 or 8.8 strength grades depending on the specific production batch. For structural or load-bearing applications, please contact us to confirm the grade before ordering.
Can these screws be used outdoors or in wet environments?
Blue zinc plating provides moderate corrosion resistance suitable for indoor and light-duty sheltered applications. For prolonged outdoor exposure, high humidity, or direct water contact, stainless steel fasteners are generally recommended. Contact us if you need outdoor-rated alternatives.
What thread standard do these machine screws use?
These screws follow the ISO metric coarse thread standard. M4 has a 0.7mm pitch, M5 has a 0.8mm pitch, and M6 has a 1.0mm pitch. They are compatible with standard metric nuts, threaded inserts, and tapped holes following ISO 68-1 specifications.
What driver bit do I need for these screws?
These screws use a Phillips (cross) drive head. For M4 and M5, a PH2 bit is typically used. For M6, a PH2 or PH3 bit is generally appropriate depending on head size. Always use a properly sized bit to avoid cam-out and head damage during installation.
What does 'countersunk' or 'flat head' mean, and when should I use it?
A countersunk (flat head) screw has a tapered underside that sits flush with or below the surface of the material when driven into a countersunk hole. This is ideal when a smooth, flush finish is required — such as in cabinetry, electronics enclosures, metal brackets, and furniture assembly where a protruding head would interfere.
How many screws come in each pack?
Packing quantity varies by diameter: M4 screws are available in 200-piece packs, M5 screws in 100-piece packs, and M6 screws in 50-piece packs. Select your preferred size and quantity combination from the variant options above.
🛒 Select your size and quantity above, then add to cart — ships from our US warehouse.
