Dead-End Spindle insulators were used extensively in the United States from the early 1900's to the mid 1920's. They were designed for use in dead ending transmission lines and for use on poles which would have high tensions from the wires or cables making sharp angles, prior to the introduction of suspension insulators. 

It was not uncommon to have an entire structure built of four to six poles to take up the strain when heavy copper wires or cables were used. Sometimes, when these heavy mechanical loads were present, these spindle insulators would be used in multiple, and the load would be distributed equally between them.

With the development and "perfection" of the now standard suspension insulator, the majority of these units were scrapped in the late 1920's and early 30's, which makes these quite scarce in collectors' circles. 

(To get an idea of how spindle insulators were used, see Robert Winkler's drawing in the May 1983 issue of Crown Jewels, page 23.) 

Shown above is a small collection of Dead-End Spindles which I have put together in the last year. All of them were in use in the Upper Peninsula of Michigan near the now abandoned Copper Mining District. The insulators are as follows, from left to right: 

1. 6600 Volt trolley style insulator. Victor R=oo (infinity symbol) embossed. This style insulator was in common use on many trolley and electric railway applications around the country. This one was found on the back end of an abandoned stamp sand dredge which was electrically powered.

2. 20,000 Volt, unembossed, 3-piece glazeweld and cemented. Most likely a Victor, as I have heard of an embossed Victor which has the glazeweld-cemented construction.

3. 20,000 Volt, Pittsburgh, date embossed. This insulator and the preceding one were from the original power house supplying Calumet, Michigan, and the mining works of the Calumet-Hecla Mining Company.

4. 30,000 Volt application. Unembossed, but a very pretty glaze. Although this one never saw any service, it was used on a front porch as a bird feeder for many years!

I feel that these insulators are important historical pieces, as the design and use of them was a vast milestone in the development of the high-tension transmission line.