DRB Seattle on tue 15 jul 08
Mel's solution points out a happy co-incidence between the threads on lamp =
parts and "Iron Pipe Thread".=A0 As anne Elk might say "My theory is this=
=A0started when lighting was in the gas-light era and gas and water plumbin=
g were the same.=A0 The thread gauge carried over when lighting was convert=
ed to e-leca-tri-si-tee.
This comes in handy for air bells on burners etc.