Spark plug thread kit The kit creates a stronger internal thread in metal and protects tapped threads from wear and damage, providing a durable for spark plug holes. Thread insert kit Ideal for restoring damaged threads in steel, cast iron, and aluminum, enabling secure and reliable spark plug installation. Thread tool Use to verify that the thread and pitch of the tap and the bolt match before installation, helping prevent cross threading and ensuring proper engagement. Key benefits Strengthens and protects spark plug threads to prevent stripping and wear. Restores damaged threads in common engine metals including steel, cast iron, and aluminum. Reduces the risk of crossthreading with a deliberate threadpitch check prior to installation. Supports reliable, longlasting spark plug seating and engine performance. What to use it for (use scenarios) Scenario 1: After removing a worn spark plug from an aluminum engine block, use the thread insert kit to rebuild the hole and restore a solid, leak seat. Scenario 2: damaged threads in a steel cylinder head to allow proper torquing and seating of a spark plug. Scenario 3: During routine maintenance, use the thread tool to confirm that the tap and bolt threads match before installing a replacement spark plug, preventing crossthreading and thread damage.