Topband: Spark gaps

[Bill Wichers]

You can get chrome steel balls too and they are *very* hard (usually
used for ball bearings). You have to drill them with solid carbide
drills. I don't think it would be possible to thread the holes using
normal taps though.

  -Bill

[snip]
> Very hard steel balls such as carbon or tungsten are ideal for
> withstanding multiple lightning strikes without need for inspection
and
> replacement, but at higher cost.