JMMRRR 30PC Helicoil Thread Repair Kit 5/16-18 — 25 Stainless Inserts, HSS Drill & Tap

This JMMRRR 30-piece 5/16-18 Helicoil thread repair kit supplies drills, tap, installation tools and 25 stainless steel inserts to restore stripped internal threads quickly and durably.

If a bolt no longer tightens or a thread is damaged in an engine block, transmission housing, or other metal part, a properly fitted wire-thread insert rebuilds the original thread size and improves fatigue resistance. The JMMRRR kit is built for 5/16-18 inch repairs and includes the drill, HSS tap, installation driver, break-off pin tool, hex wrench and 25 inserts stored in a compact box so you can complete common automotive and mechanical restorations on the spot.

How does this kit restore stripped 5/16-18 inch threads?

The process is straightforward: drill to the specified diameter, tap to the new insert thread form, drive the Helicoil insert into the hole, then snap off the tang. The kit supplies the correct HSS drill and tap sized for 5/16-18 inserts so repaired holes match the bolt dimensions while the stainless-steel coils add wear resistance.

• Includes 1 HSS twist drill sized for the kit and 1 screw tap matched to the inserts
• 25 stainless-steel wire inserts restore original 5/16-18 thread engagement
• Installation driver and break pin tool ensure proper seating and tang removal

What materials and design features make this kit reliable?

JMMRRR uses precision stainless-steel wire for the inserts to resist corrosion and increase connection strength. The HSS tap and 135° twist drill offer accurate cuts and efficient penetration in softer metals like aluminum, while rubberized grips and engraved markings improve control and speed during use.

• Stainless-steel inserts for durability and fatigue resistance
• High-speed steel (HSS) drill and tap for precise, long-lasting threads
• Ergonomic handle and labeled tools for safer, faster operation

Which applications is this 30-piece set suited for?

This kit is optimized for automotive and light industrial thread repairs where original 5/16-18 bolt fit is required. It works well on engine components, transmission housings, machinery panels and other soft metals or worn tapped holes that need a reinforced internal thread.

• Engine and automotive repairs: cylinder head, intake manifolds, brackets
• Maintenance of gearboxes, pumps and light machinery housings
• Field or shop use thanks to compact storage and clearly marked tools

Who is this for? The JMMRRR 30PC Helicoil kit is aimed at mechanics, DIYers and maintenance technicians who need a compact, complete solution to restore stripped 5/16-18 threads without replacing parts. If you routinely work on engines, restore equipment, or perform preventive maintenance on assemblies made from softer metals, this kit gives the right drill, tap, inserts and tools—organized in a portable case—to make secure, repeatable thread repairs.