KUNGJUER 5/16-18 Helicoil Thread Repair Kit, 30pc — Stainless Inserts, HSS Tap & Drill

KUNGJUER's 30-piece 5/16-18 Helicoil thread repair kit supplies every tool and insert needed to restore stripped or damaged SAE threads fast and reliably.

This compact kit is built for rethreading 5/16-18 inch holes in engines, machinery, and metal assemblies. It gathers a drill, tap, insertion and break-off tools, 25 stainless-steel inserts and a wrench in a protective case so you can repair worn threads on aluminum, iron, steel and other common metals without hunting for extra parts. The components are designed for durability and consistent alignment to produce strong internal threads that resist wear.

How do I use this kit to repair a stripped 5/16-18 thread?

Repairing a damaged hole is a three-step process: drill to the specified size, tap the new thread form, and install the helicoil insert before breaking off the tang. The kit contains parts sized specifically for 5/16-18 work so each step aligns correctly and the finished thread matches the original fastener dimensions.

• Use the 135° twist drill to clear the old thread and reach the correct diameter (≈8.3 mm).
• Run the HSS tap to cut the new coarse thread profile cleanly and squarely.
• Drive a stainless-steel insert with the installation tool and snap off the breaking pin with the provided breaker.
• Verify fit with the hexagon wrench and test with the original bolt.

What materials and parts are included, and will they hold up under repeated use?

The kit combines high-speed steel and precision stainless-steel wire components for long service life. The drill and tap are made to handle soft and medium metals, while the inserts are corrosion-resistant and strengthen the repaired thread against repeated assembly cycles.

• 1 twist drill (135°) for clean hole preparation.
• 1 HSS screw tap sized for 5/16-18 threading.
• 1 insertion tool and 1 break-off pin tool for accurate install and tang removal.
• 25 stainless-steel helicoil inserts plus a hex wrench and fitted storage box.

How versatile is this kit for automotive and workshop jobs?

This SAE-focused set is intended for common automotive tasks like cylinder head bolts, engine brackets and accessory mounts, but it also works for industrial hardware and DIY metal repairs. The drill, tap and inserts are suitable for aluminum, iron, carbon steels, bronze and magnesium, covering most shop scenarios where thread reinforcement is needed.

• Engine repair: restore stripped bolt holes in heads and blocks.
• Machinery maintenance: renew threads on housings and flanges.
• Fabrication and restoration: strengthen threads in softer alloys.
• Home workshop jobs: fix stripped bolts in tools, mounts and brackets.

What features make this kit convenient to carry and work with?

Organization and ease of identification speed up repairs. The metal storage case keeps every piece in place, while the drill and tap have engraved size markings for quick selection. The ergonomic handling surfaces and compact layout help when working in tighter engine bays or on-site repairs.

• Durable iron carry case with dedicated slots for each tool and insert.
• Engraved markings on the drill and tap for fast identification.
• Ergonomic handle on hand tools for improved grip and control.
• 25 spare inserts so you can perform multiple repairs without restocking.

Who is this for? The KUNGJUER 30PC 5/16-18 Helicoil kit fits mechanics, fabricators, maintenance techs and serious DIYers who need a reliable rethreading solution for SAE-sized fasteners. If you work on engines, metal assemblies or routinely repair threaded holes in soft to medium metals, this all-in-one set provides the correct tools and enough inserts to complete several repairs with professional results.