They are a pretty basic tool but very much needed to set the correct gap on the spark-plugs, (and points, if your car has them.). You find what the gap should be on the plug, get the appropriate guage, and fit it into the gap.....tap in a bit, if too big, widen a little if too narrow..... :thumbsup:
Best advice I had on what the "feel" should be is that it's like dragging a sharp knife through a nice chocolate cake...firm but not too hard to pull through.
mmm....damn, now I'm thinking of chocolate cake.... :yeah:
