BILITOOLS 5/16-18 Thread Repair Kit — HSS Drill & 304 Stainless Helicoil Inserts, Complete SAE Set

BILITOOLS 5/16-18 Thread Repair Kit is a complete HSS drill, tap, and 304 stainless Helicoil insert set designed to restore stripped 5/16-18 internal threads and create stronger, longer-lasting repairs. If a bolt hole has been stripped or damaged, this repair kit provides the tools and corrosion-resistant inserts to rebuild the thread to proper specification without replacing the host component. The set is made to work across metals, composites and polymers commonly found in automotive, plumbing, and machinery applications, and it ships organized in a durable iron case so you can take it between jobs with everything in place.

How does this kit rebuild a stripped 5/16-18 thread?

The repair process uses a stepped workflow: drill the damaged hole to the correct oversize, use the included tap to cut the Helicoil seat, install a 304 stainless thread insert, and break the tang off once installed. The stainless insert restores the original thread pitch while providing a harder, wear-resistant surface for repeated torque cycles.

• Includes HSS drill sized for 5/16-18 oversize preparation
• High-quality tap cuts the insert seat precisely
• 304 stainless Helicoil inserts re-create the 5/16-18 internal thread
• Break pin tool removes the installation tang cleanly

What materials and applications does it work with?

This SAE kit is suitable for steel, aluminum, cast iron, brass, plastics and composite housings where original threads have failed. Because the inserts are stainless steel, they resist corrosion and increase the load-bearing capability of repair sites in weaker base materials.

• Compatible with most metals and engineering polymers
• Commonly used in automotive engine blocks, transmission cases, and manifolds
• Useful for plumbing fittings, pump housings, and light machinery frames
• 304 stainless inserts extend service life versus tapped base metal

What components come in the kit and how are they organized?

The BILITOOLS kit bundles all required items—HSS drill, dedicated tap, multiple stainless inserts, an installation tool and the break pin tool—so you won’t need extra parts for a standard repair. Everything is arranged in an iron case with cutouts and labels for quick access on the bench or in the field.

• HSS drill and 135° apex drill geometry for efficient penetration
• Tap matched to the insert seat profile for reliable engagement
• Installation tool and break pin tool for clean, repeatable installs
• Compact iron case for transport and storage between jobs

How do I choose the right kit size and avoid mistakes?

Confirm the original thread pitch and diameter before buying—this set is specifically for 5/16-18 UNF/UN threads. If you’re unsure which size you need, consult the illustrated sizing guide included in the product images or test with a thread gauge to match the pitch and major diameter.

• Verify original thread is 5/16-18 before drilling
• Use the provided sizing illustration for reference
• Follow torque and lubing recommendations for best results
• Practice on scrap material if you are new to Helicoil installs

This kit is for mechanics, maintenance technicians, DIYers and fabricators who need a reliable way to restore stripped 5/16-18 internal threads without replacing components. If you work on vehicles, small engines, plumbing fixtures or industrial equipment and value repeatable, corrosion-resistant repairs in the field or shop, the BILITOOLS set gives you the drill, tap, inserts and tools organized in a rugged case so repairs stay consistent and fast.

FAQ

Q: Is this kit compatible with aluminum engine blocks?

A: Yes. The kit’s 304 stainless inserts are designed to strengthen repaired threads in aluminum and other softer metals.

Q: Does the set include enough inserts for multiple repairs?

A: Yes. The kit contains multiple 5/16-18 stainless inserts so you can complete several repairs before restocking.