Product Highlights

✅ Must-Have Spark Plug Thread Repair Tool
Perfect for fixing severely cross-threaded & damaged spark plug holes without removing the cylinder head. No thread insert needed – saves massive labor time and maintenance costs.

✅ Zero Metal Shavings Falling Into Engine Cylinder
Coat the tool threads with grease before use – grease traps all metal chips inside the tool grooves, and shavings are fully removed with the tool. No risk of debris damaging your engine.

✅ Premium 42CrMo Alloy Steel Construction (Equivalent to 4140 Steel)

• High tensile strength & excellent toughness

• Great hardenability, nearly no temper brittleness

• High fatigue resistance & repeated impact tolerance after quenching and tempering

• Outstanding low-temperature impact toughness

• Robust, wear-resistant, precise, and long service life for heavy-duty workshop use

✅ Complete 7-Piece Back Tap Kit – Multiple Sizes & Lengths
Covers mainstream spark plug thread specs for most cars, motorcycles, and small engines:

• M8×1.0 – Total Length: 4.5"

• M10×1.0 – Total Length: 4.5"

• M12×1.25 – Total Length: 5.27"

• M12×1.25 – Total Length: 10.3"

• M14×1.25 – Total Length: 5.27"

• M14×1.25 – Total Length: 10.3"

• M18×1.5 – Total Length: 3.4"

Long & short dual lengths for M12×1.25 / M14×1.25 – fits more vehicle models widely.

✅ Built-In Chip Groove Design
Pre-set thread grooves collect metal shavings during rotation reliably, completely protecting your engine from internal foreign matter damage.

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Step-by-Step Operation Instructions

1. Coat with Grease or Anti-Seize Lubricant
   Wipe the tap clean, then apply proper grease or anti-seize compound onto the tool threads.

2. Slowly Expand Damaged Thread Gradually
   Insert the tool vertically into the spark plug hole. Do NOT set to maximum expansion on the first attempt – widen the damaged hole little by little in 3–5 passes.
   If rotation gets stiff, swing the tool slightly left and right, apply moderate force, and keep slow operation. When meeting hard resistance, back off slightly then advance again.

3. Take Out & Clear Metal Chips
   Retract the tool tap by twisting the handle knob, open the thread chip groove, and fully clean accumulated shavings. Reset the tool head and reapply grease for next use.

⚠️ Do not over-tighten the knurled adjustment knob – loosen it immediately if excessive resistance occurs during withdrawal.

4. Repeat Until Thread Restoration Finished
   Reinsert the tool and perform cyclic trimming. All residual debris will be captured inside the groove and removed externally. Complete spark plug thread repair safely without engine disassembly.

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Wide Application
Universal repair kit for spark plug thread damage on most cars, motorcycles, and small engines – ideal for auto repair shops, mechanics, and DIY enthusiasts.