Malco HW6X3/8Z
•A unique thread design and quality controlled manufacture spell the Zip-in difference.
•Zip-in’s sophisticated heat treat process allows the screw to taper to a fine, sharp point without sacrificing critical point strength.
•Zip-in screws are faster driving, with a greater capacity for fastening heavier gauges of sheet metal than any other self-drilling type.
•Undercut-indented hex washer slotted head always seats flush.
•Full 1/4 in. (No. 8) head will not strip out of hex driver opening at any-time during operation.
•Complete operator control with precise hole alignment.
Meet Malco Zip-In HW6X3/8Z Self-Piercing Screws—the fast, dependable solution for joining thin sheet metal with precision. This 6×3/8″ self-piercing screw features a zinc-plated finish and a 1/4″ slotted hex washer head, designed for quick, secure fastening in metal enclosures, HVAC ductwork, automotive panels, and more.
- Unique thread design for instant bite:A single starting thread is formed down to the very tip of the point, the source of Zip-In’s penetrating power from the first contact.
- Double-thread engagement for rapid penetration:A second thread above the point engages after initial penetration, drilling in double fast for efficient installation.
- Heat-treated for sharp, durable points:A sophisticated heat-treat process tapers to a fine, sharp point without sacrificing critical point strength.
- Faster driving and heavier-gauge capability:The Zip-In design delivers quicker fastening and greater capacity for heavier gauges of sheet metal than any other self-piercing type.
- Corrosion-resistant finish:Zinc plating protects against rust in exposed or humid environments, helping maintain long-term performance.
- Bulk quantity for large projects:Packaged in a generous 18,000-count bundle, ideal for continuous work on multiple panels or installations.
Ideal use cases
- HVAC ductwork and metal housings where fast, reliable piercing is essential.
- Automotive body panels, instrument enclosures, and electrical cabinets requiring consistent bite and strong pull-out resistance.
- Metal roofing, siding, and panel assemblies that demand a robust self-piercing fastener with rapid installation.
Why choose Zip-In over traditional self-piercing screws?The combination of the tip-first thread, second-thread engagement, and optimized heat treatment translates to faster, cleaner assemblies with fewer misdrives and reduced stripping risk. It’s a practical, high-performance choice for professional installers and serious DIYers tackling metal projects.
Pro tips for best results
- Use a compatible driver with a 1/4″ hex washer head to maximize contact and drive efficiency.
- Keep the mating metal surfaces clean and aligned to ensure the threads engage smoothly from the first bite.
- Avoid over-tightening to protect the fastener’s clamping power and prevent panel distortion.


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