By Ross Padluck
I’ve been collecting insulators for a very long time - enough to put together a collection that has slowly taken over the house. Glass insulators were developed in the nineteenth century to insulate electrical and telegraph wires from poles.
The Hemingray Glass Company produced the majority of North American Insulators. I keep most of my collection in backlit displays – creating a beautiful showcase of the various colors of glass, shapes and sizes of these fascinating objects.
They were held to the telephone polls on wood crossarms and supported with threaded wooden pins. The glass prevented voltage from being transferred through the pole to the ground. The Hemingray patented glass points running along the bottom rim are called Drippoints, which help prevent rainwater from siphoning under the glass and rotting the wood pins. The hundreds of designs are all well documented as CD’s – Consolidated Design – numbers. Here are some of my favorites:
CD 162 – Hemingray No. 19 in Cobalt Blue. This one is a little worn but shows beautifully. The rich, deep colors on these "Signal" insulators are highly collectible.
CD 235 – Pyrex No. 662 in Carnival Glass. The iridescent colors on this piece are spectacular!
CD 257 – Hemingray No. 60 in Hemingray Blue. Nicknamed "Mickeys" because of the ears, the 1890-patented saddle groove in the glass supported wires carrying loads of up to 6600 volts.
CD 303/310 Hemingray No. 76 "Muncie Type" in Hemingray Blue. These large two-piece glass insulators were mostly used in Montana to carry long-range transmission lines of up to 55,000 volts. The Hemingray factory was in Muncie, Indiana. Beside this is a CD 734 Victoria threadless insulator, a very early piece from 1875, for a size comparison.
CD 248/311/311 Hemingray No. 79 in Hemingray Blue. Known as the "Montana Stacker" this 3-piece insulator was used on high voltage lines in Montana as well. I bought mine from a collector whose father was a Montana lineman. I carried this onto the tiny jet on my way home. For reasons unknown, I had to recheck my bags in Denver and the TSA agent was baffled by this thing. Later, I needed clearance to carry it on the connecting flight! Fortunately it made it home in one (three) pieces.