A New Patent Top Porcelain

Reprinted from "INSULATORS - Crown Jewels of the Wire", October 1972, page 28

This has to rate as our top porcelain news of the month. The U-401 shown at the right turned up at the Kansas City show. I had a chance to buy it but deferred to my friend, John Hall of Columbus, Ohio. As it later turned out, this was John's good fortune. We immediately speculated about this unusual design and correctly guessed that the small pair of ears on each side of the crown were for accommodating some form of clamp to hold something inside the large, circular depression in the crown.

We now have the answer - both in the form of porcelain and paperwork. John located in another collection a second specimen accompanied by a porcelain "cap", 1" x 1- 3/8", which fits inside the crown hole to hold the conductor tightly in place.

This cap has a small top dimple, and John and I had speculated that it was to be held down with a wire bail over the top of the insulator.

With some real luck, the old Ohio Brass Co. drawing files yielded a drawing of this complete insulator (dated Oct. 12, 1910), and I'll have a reduced drawing of it in next month's column. The metal part is not a wire bail but is a large, semi-circular casting with a threaded thumbscrew through the top and which tightens down on the cap.

It would be great if we could locate more of these, or at least a metal clamp for one.