Kolvoii Metric Helicoil Thread Repair Kit 156-Piece — M5–M12 Repair Set with HSS Drills & 304 Stainless Inserts

Kolvoii’s 156-piece metric Helicoil kit provides everything needed to repair and reinforce stripped metric threads from M5 to M12 in a compact, organized case.

This complete metric thread repair system bundles drill bits, taps, stainless steel wire inserts, installation and break-off tools to restore damaged threads and recreate durable, wear-resistant female threads in soft and hard metals. The kit’s components are sized for the most common metric fasteners and are packaged for easy storage and transport, making on-the-job or garage repairs fast and repeatable.

What sizes and parts are included in the kit?

The Kolvoii set covers standard metric sizes M5, M6, M8, M10 and M12 and supplies the matched tools for each size so you can complete a repair without hunting for extras. Parts are counted and organized to support multiple repairs of each size.

• 135 stainless steel wire Helicoil inserts (various counts per size)
• 5 drill bits (135° apex angle), 5 matching taps, 5 installation tools
• 5 break-off/break-off pin tools and 1 hex wrench for insert seating

How do I use the kit to repair a stripped thread?

Repairs follow a clear three-step workflow: Drill, Tap, Install. The kit’s drill bits and taps are heat-treated HSS for reliable cutting, and the installation tools seat the stainless inserts to form new internal threads that accept the original fastener size.

• Drill to the specified oversize using the included HSS drill bit
• Tap the hole with the supplied tap to match the Helicoil outer diameter
• Install the stainless insert, then break the tang for a flush finish

Which materials and applications does this Helicoil kit work best on?

This kit is intended for use in a wide variety of base metals where thread reinforcement or restoration is needed. It is commonly used in engine blocks, cylinder heads, machinery housings, and other components made from aluminum, iron, carbon steel and bronze.

• Suitable for aluminum and softer alloys where thread wear is common
• Also effective in ferrous metals such as cast iron and steel
• Frequently used for automotive, motorcycle, marine, and industrial repairs

What makes the Kolvoii kit durable and easy to use?

Tooling quality and organization are central to this kit: heat-treated HSS drills and taps maintain sharpness under load, while 304 stainless inserts resist corrosion. The ergonomic, rubber-coated grips and the durable carry case keep components accessible and controlled during repeated repairs.

• HSS drill bits and taps for long-lasting cutting performance
• 304 stainless wire inserts for corrosion resistance and strength
• Rubber-coated handles and a custom case for comfortable, organized work

Who this kit is for: Mechanics, fabrication shops, maintenance technicians and home DIYers who need a reliable, portable thread-repair solution will find the Kolvoii 156-piece metric Helicoil kit well suited to repetitive or emergency thread restoration tasks. It’s especially useful when replacing a component isn’t practical and preserving the original bolt pattern and size is important.