We take cryptocurrency — so the coins you hold can buy real hardware.Pay in crypto, spend it on real hardware. Free insured shipping worldwide over $399. Plain, unbranded boxes, sent from Germany.Free insured shipping over $399. Your rate is locked for 30 minutes once checkout opens.Rate locked 30 minutes. Every item sealed, serial-checked and covered by a 24-month warranty.Sealed, 24-month warranty.

Saved items Sign in

Helicoil

Helicoil 5523-14 Thread Repair Kit M14x1.25 304 SS 30 Pcs

SKU CH-S503-J23VR

Repairs M14x1.25 threads using 304 stainless steel inserts in six lengths from 9.525 mm to 19.05 mm

  • TypeAlignment Tools
  • Restores damaged M14x1.25 threads with precision
  • 304 stainless steel inserts resist corrosion long-term
  • 30-piece kit covers multiple repair scenarios
  • Six insert lengths from 9.525 to 19.05 mm
  • Tanged free-running design ensures reliable installation

Helicoil 5523-14 Thread Repair Kit

The Helicoil 5523-14 kit provides 304 stainless steel helical inserts for M14x1.25 metric threads. It contains 32 pieces including six inserts across five lengths from 9.525 mm to 19.05 mm plus a special STI tap. Designed for free-running installation in metal components.

Mechanics repairing stripped spark-plug

Suits technicians restoring M14x1.25 threads in aluminium or steel heads. The single-size, tanged inserts limit use to this specific pitch and diameter. Builders needing multiple thread sizes or tangless inserts should look at something else.

Verify the damaged hole matches M14x1.25 before

Confirm the parent material accepts 18-8 stainless inserts and that a special STI tap is available. The kit includes no drill bits, so the correct pilot diameter must be sourced separately. Ensure the insert lengths offered cover the required engagement depth.

Highlights

  • Restores damaged M14x1.25 threads with precision
  • 304 stainless steel inserts resist corrosion long-term
  • 30-piece kit covers multiple repair scenarios
  • Six insert lengths from 9.525 to 19.05 mm
  • Tanged free-running design ensures reliable installation

Specifications

BrandHELI-COIL
TypeAlignment Tools

Questions about this item

What tap size must I already have to install the M14x1.25 inserts in this kit?

The kit includes a special STI tap for M14x1.25 threads; you will need that tap to cut the oversize holes before inserting the helical coils.

Will these 304 stainless-steel inserts gall when installed into an older aluminium cylinder head?

The 18-8 stainless inserts are free-running and designed for metal parent material; using proper lubrication during installation prevents galling in aluminium heads.

How can I verify the inserts are seated correctly after installation?

After driving each insert with the installation tool, the tang should break off cleanly at the notch and the top coil should sit flush with or slightly below the surface.

Also in this aisle

People compared these

Same shelf, same checkout — eight coins and a 30-minute rate lock.