E-Z Lok SK40420 Metric Helical Threaded Insert Kit, 304 Stainless Steel, M4-0.7 Thread Size, 8 mm Installed Length (Pack of 10)

Description

Product Overview

The E-Z Lok SK40420 Helical Insert Kit is engineered to restore and reinforce threaded holes in a variety of soft metals. Each kit contains ten 304 stainless steel helical inserts sized for an M4‑0.7 thread, providing a durable, corrosion‑resistant solution that can withstand temperatures up to 800°F. The kit also includes a precision drill bit, a stainless‑steel STI tap, a dedicated installation tool, and tang break tools, giving you everything needed for a complete repair without additional purchases. The inserts are designed with a continuous helical coil that expands as it is driven into the tapped hole, creating a strong, permanent thread that distributes load evenly across the surrounding material. This design eliminates the common failure points found in traditional solid inserts, especially in softer substrates like aluminum, cast iron, and magnesium.

Usage

This kit is ideal for both professional maintenance environments and hobbyist workshops. Use it to repair stripped or damaged threads on machine components, automotive parts, aerospace brackets, and custom fabricated pieces. The installation process begins with drilling a pilot hole to the recommended diameter, followed by tapping with the included STI tap. The helical insert is then driven into the tapped hole using the supplied installation tool, which provides controlled torque and alignment. After the insert is fully seated, the tang break tool removes the excess tang, leaving a clean, flush surface ready for a standard M4 bolt. The kit’s versatility makes it suitable for repairing equipment in manufacturing plants, repairing prototype assemblies, or performing on‑site field repairs where downtime must be minimized.

Why Choose Us

Choosing the E-Z Lok SK40420 means selecting a product backed by decades of fastener expertise and rigorous quality control. Each stainless steel insert is manufactured to meet ASTM standards, ensuring consistent dimensions and material integrity. The kit’s comprehensive component list reduces the need for multiple suppliers, streamlining inventory management and cutting overall repair costs. E‑Z Lok provides detailed installation instructions and offers technical support for any questions that arise during the repair process. Our commitment to durability is reflected in the 5‑star customer rating, based on real‑world performance in demanding applications. Additionally, the kit’s corrosion‑resistant construction extends the service life of repaired parts, protecting investments and reducing the frequency of future maintenance cycles.

Key Features

• High‑strength 304 stainless steel inserts resist rust and maintain performance at temperatures up to 800°F.
• Helical coil design expands within the hole for a secure, load‑spreading thread that outlasts solid inserts.
• Complete repair set includes drill, tap, installation tool, and tang break tools—no extra purchases required.
• Easy installation process suitable for both seasoned technicians and DIY hobbyists, reducing downtime.
• Dedicated after‑sales support and detailed instructions ensure confidence from start to finish.

FAQ

What types of metal can I use this kit on?

The SK40420 kit is optimized for soft metals such as aluminum, cast iron, magnesium, and similar alloys. The stainless steel inserts provide a hard, durable thread that works well with these softer substrates, preventing further stripping.

Can I install the inserts in an existing damaged thread without re‑tapping?

While the kit includes a tap for creating a fresh thread profile, the helical insert can also be used to reinforce an existing damaged thread if the hole is cleaned and slightly enlarged to accommodate the insert’s outer diameter. For best results, follow the recommended drilling and tapping steps.

How do I break off the tang after installation?

The kit provides a tang break tool specifically shaped to snap off the excess portion of the insert cleanly. Position the tool against the protruding tang and apply a firm, controlled force; the tang will fracture, leaving a smooth surface ready for the bolt.

Is the kit compatible with standard M4 bolts?

Yes, the inserts are sized for M4‑0.7 threads, making them fully compatible with standard M4 bolts and screws commonly used in industrial and consumer applications.

What warranty does E‑Z Lok offer on this product?

E‑Z Lok provides a limited one‑year warranty covering material defects and manufacturing errors. If you encounter any issues within this period, contact our support team for a replacement or refund.