On Sat, 6 Dec 2014 15:21:32 -0600, "Terry Coombs"
wrote:

Jeff Wisnia wrote:
I'll bet most of you aren't old enough to have seen a spark plug like
this one I've got in my "Hell box".

http://home.comcast.net/~jwisnia18/jeff/plug.html

Jeff

I've got a pair that are similar , came in the heads of my 1939 HD ...
but they seal to the head with a copper washer rather than using tapered
threads .
The plugs in my '28 Chevy were "rebuildable" plugs as well. Lots of
aircraft plugs too.
None of them were pipe-thread though, thank goodness.

Some current plugs are 2 piece too - like the infamous plugs in the
5.7 Fords that come apart when you try to remove them.