Reprinted from "Crown Jewels of the Wire", November 1987, page 28
I am most grateful to Mr. N. R. Woodward, Houston, Texas, for his willingness
to answer reader's questions. Mr. Woodward is the author of The Glass Insulator
in America and developed the Consolidated Design Numbers identification system
for glass insulators.
Question: What, if anything, can you tell about the age of an insulator from
the patent date? (Ed Haas, Omaha, Nebraska)
ANSWER: Patent dates are of only limited value in determining the date an
insulator was actually produced. The only thing certain is that it was
manufactured after the latest patent date shown thereon. Normally molds were not
engraved with the patent date after the patent had expired. That could vary
depending on whether a renewal was granted. And, too, there would be no reason
why the mold shop would rush to remove the date from existing molds when it
expired. In most cases, the molds were probably used until they wore out without
going to the expense of removing dates that referred to the expired patents.
Question: I would like to know if you have ever heard of the following
HEMINGRAY - 20 / MADE IN U.S.A.
Both the "E"s in Hemingray and Made are missing the middle bar.
(Jack O'Neal, Middle Island, New York)
ANSWER: I have no record of ever having seen the HEMINGRAY-20 with the two
unfinished "E"s. You did not specify the time period involved; but for
a popular style like the 20, they had several hundred molds throughout the years
it was made. In engraving all of those molds, parts of letters, or even entire
letters, were occasionally left off. In the case of the missing bar in the E, it
could easily have been added later, so perhaps that "error" existed
during one production run only.