The tap gradually cuts the 10mm slightly wider so that the thread is cleaned up, and you can fit the machined aluminium insert into the spark plug hole. If you have a cross threaded 10mm x 1mm spark plug in an Aluminium head, then this is the perfect little kit to rectify it.
18mm Spark Plug Thread Repair Kit - Handy Force Co., Ltd
Spark Plug Threader Tool,Spark Plug Repair Kit Spark Plug Threader Kit Spark Plugs 25 Pcs Car Spark Plug M14*1.25 Tap Screw Thread Tools Repair Kit With Case : Automotive
THREADED PIPE SIZE: M10x1.0 (thread diameter x pitch). Universal size is suitable for repairing spark plug thread M10x1.0, very useful and convenient.
Spark Plug Thread Repair Tool, M10x1.0 Bolt + M12x1.0 Tap Auto Accessories Hardware Kit Stainless steel
Spark Plug Thread Repair Tool, M10x1.0 Bolt + M12x1.0 Tap Auto Accessories Hardware Kit for Gasoline Engines, Generators : Automotive
M10 X 1.0 Spark Plug Repair Kit Spark Plug Thread Repair Kit M10X1.00 Stainless Steel Spark Plug Thread Repair Tool M10X1.0 Bolt M12X1.0 Tap Auto Accessories Hardware Kit : Automotive
TIME-SERT kit includes 3 inserts 15mm reach and 2 inserts 9mm reach Fast and reliable repair by Time-Sert M10x1.0 spark plug repair kit First time
TIME-SERT M10x1.0 Spark Plug Thread Repair kit with Inserts P/n 4010-103
Spark Plug Thread Repair Tool, M10x1.0 Bolt + M12x1.0 Tap Auto Accessories Hardware Kit Stainless steel : Automotive
OEMTOOLS 25632 M10-1.5 Fix-A-Thread Spark Plug Thread Repair Metric Kit : Automotive
Material: tool steel Thread sizes: M10 x 1,0mm Content: thread cutter, 4 thread inserts (9,5 / 11,5 / 12,7 / 19 mm long)
Spark Plug Thread Repair Kit M10 x 1.00