The engine stop device is really quite easy.
Using a thread pitch gauge and a micrometer, determine the thread and pitch of your spark plug.
If you don't have a thread pitch gauge and micrometer (you should), get the spark plug number of the spark plug you are using and use Google (or your favorite search engine) for a spark plug thread pitch chart.
Once you know the thread and pitch, then a trip to your FLAPS for a bolt of the correct thread and pitch. The bolt should have sufficient thread to extend about an inch further than the spark plug into the cylinder.
I think what Jerry was referring to with the spark plug shell, was to remove the complete electrode assembly from a defective spark plug, drill out and thread the center for a bolt to replace the electrode. Then you don't have to worry about the thread size and pitch, as you are using an old (modified) spark plug.
Martin - there probably is such a thread here somewhere, but a thread on "essential" (other than pliers and screwdriver
) tools for the enthusiast might be useful.
Jon.
