KUNGJUER Helicoil Metric Thread Repair Insert Kit

The KUNGJUER Helicoil Metric Thread Repair Insert Kit M12x1.75 is a complete rethreading solution for restoring damaged M12 threads quickly and reliably.

If a stud, bolt, or tapped hole has stripped threads, this M12 repair kit gives you everything needed to return the part to usable condition without replacing the whole component. The set bundles a drill, HSS tap, installation and break-off tools, coil inserts, wrench, and a durable storage case so you can repair internal threads in engines, panels, or machinery using aluminium, steel, magnesium and other common metals.

How does this kit restore stripped M12x1.75 threads?

The kit works by enlarging the damaged hole to a controlled size, cutting a new thread with the supplied tap, and inserting a stainless steel helicoil to recreate the original M12x1.75 female thread. The helicoil forms a hard, wear-resistant internal coil that accepts the original bolt size and pitch.

• 12.4 mm twist drill to clear the damaged threads
• High-speed steel tap that cuts precise M12x1.75 threads
• Stainless steel inserts that act as new internal threads
• Break-off tool to remove the installation tang cleanly

Which materials and applications are suitable for these inserts?

This set is designed for use in soft and medium-hard metals where original tapped threads may fail—aluminium, iron, carbon steel, bronze and magnesium are all supported. Typical uses include automotive engine blocks, gearbox housings, exhaust brackets, and structural components requiring strengthened threads.

• Engine and automotive repair: restore bolt holes in cylinder heads and blocks
• Maintenance of industrial equipment and small machinery
• Marine and hobby fabrication using soft alloys
• Anywhere a durable M12 thread replacement is needed

What tools are included and how do they make repairs easier?

The kit supplies each step’s tool so you don’t need additional parts: a dedicated drill clears damaged material, a precisely ground HSS tap forms the correct thread profile, and an installation tool seats the helicoil properly. An ergonomic handle, hex wrench, and breaking pin tool improve control and finish, while the engraved bits aid fast identification on the job.

• Drill bit (≈12.4 mm) and HSS tap matched for M12x1.75 inserts
• Installation tool and breaking pin for secure seating and tang removal
• Hex wrench for controlled insertion and torque
• Compact iron carry case for organized storage and transport

How durable and precise are the helicoil inserts?

Each insert is manufactured from precision stainless steel wire to offer corrosion resistance, improved wear properties and consistent thread engagement. Using a helicoil replaces the weak original thread surface with a tougher, fatigue-resistant coil that helps prevent future stripping.

• Stainless steel coils for strength and corrosion resistance
• Consistent dimensional tolerances for secure bolt fit
• Improved fatigue life compared with damaged tapped holes
• Suitable for repeated bolt changes and maintenance cycles

Who is this for? Technicians, mechanics, home DIYers, and maintenance personnel who encounter stripped M12 threads and want a reliable repair without replacing parts will find this kit useful. It’s aimed at people who need a compact, complete solution for rethreading M12x1.75 holes in engines, equipment, or metal fabrications and who value clear tool identification, durable inserts, and a portable case for on-site repairs.