You may have heard about some old four-part insulators with concentric rings under the top skin, which have been coming out of California recently. Bill Rohde has been very active over the past two years in an effort to collect old multipart porcelain insulators, and he has been responsible for making available most of the ringed insulators. Bill has managed to capture all of the known variants of these old classic ringed insulators. We give a special thanks to Bill for sorting out which styles have rings, how many rings each have, and especially for some beautiful photographs of these specimens. Nearly all of the photographs that appear this month were taken by him. You will have to wait for the second edition of my book, Multipart Porcelain Insulators, to see what these look like in color. The book will be ready next year, and will include a dozen or more 4 x 6 color photographs of beautiful classic multipart styles such as the ringed insulators, gray lily-shell styles, and many more.

What we mean by rings under the top skirt can easily be seen in the following photograph. The concentric rings are actually short petticoats that were used to increase the electrical leakage distance. These rings may be the forerunner of the single and double petticoats seen under the top skins of more modem multipart insulators. The rings may be better described as corrugations.

4-part insulators with 6, 13, 9 and 10 rings

An insulator with rings or corrugations was designed by Frank G. Baum (of San Francisco), and claimed as novel in a patent that was granted to him on December 11,1906 (see patent drawing). The primary claim of the Baum patent was the use of a ribbed, tubular insulator that would hold the conductor, and be clamped on top of a multipart insulator. The horizontal, ribbed insulator would be easily washed by rain. A secondary patent claim was made for the corrugations on the interior surfaces of the skirts. The use of a supplemental ribbed insulator is an obviously complicated and expensive design, but the corrugations would be an easy feature to include in actual production.

Albeit that adding the corrugations to the lower skirts proved too difficult, especially for Thomas. Remember that, before 1910, Thomas specimens have the "blue-jean seam" marks inside the bottom skirt. They evidently had enough difficulty making a smooth interior surface without adding corrugations. It seems that they used blue-jean pants legs to prevent the forming-plunger from sticking to the interior surface. The denim material could then be easily removed and reused. Bill suggests that the use of the pants legs may have had something to do with forming the threads, since the threaded section is the only part that shows evidence of a blue-jean seam. Perhaps the threads were formed In the same operation as that used to press the shape of the bottom shell.

Adding the corrugations to the top, flat skin would be easy, since the forming plunger was pressing against a relatively flat surface. The primary concern in 1905-06 was to provide adequate leakage distance by adding a recessed fourth shell. It would be so much the better to add the corrugations, as this would eliminate the need to either make the insulator larger, or to add a fifth shell, both of which would increase the size and weight of the insulator.

The only known specimens of these ringed insulators have been found in California. In fact, a few of them are still in scattered service. Many of the surviving specimens have been removed during the last few years, with only a small percentage of these ever getting into collector's hands. Consequently, all of the ringed insulators are quite rare. Less than eight of each of the four styles have been accounted for in collections. The 6-ringed specimens appear to be the rarest, with perhaps less than four known.

Two manufacturers have been identified who made these insulators. Thomas made the majority of the specimens as identified by blue-jean seam marks found on the inside of the fourth skirt. None of the specimens were marked "THOMAS". Below is a list of the Thomas ringed styles:

Note that M-4415A is essentially identical to M-4415, made by Thomas, but it does not have rings under the top skirt. Most of the Thomas specimens have a beautiful mustard yellow glaze with varying amounts of rusty red. The specimens are very pretty, which adds greatly to collector interest. It seems odd to me why Thomas offered the same insulator with two different numbers of rings. I would not believe that 10-rings would be significantly more effective than one with 6-rings. The difference was probably due to the whim of the purchaser.

M-4415 showing 6 rings

M-4325C showing 9 rings

M-4415 showing 10 rings

The second manufacturer was Lima Insulator Co. As you may know, Lima was in operation from 1904 until September, 1908 when the factory was destroyed by fire. Lima made only one style of ringed insulator:

Bill acquired the only marked M-4600 when he purchased Mike Guthrie's collection. That specimen is marked, "LIMA, N.Y. " J (see the photograph below)! All of the M-4600 specimens have a rich mahogany glaze.

M-4600 13 rings

LIMA, NY incuse marking on the side edge of insulator's crown

I recently acquired an original Lima catalog No.1 from one of Fred M. Locke's granddaughters. The next page shows the illustration of style 64 from that catalog which we have assigned M-4600. Note that style 641is identical to M-4600 except that it may be ordered without the rings. This style has been assigned M4600A, but a specimen has not been found.

Note my advertisement this month for fine quality reprints of this 1904 Lima catalog, the 1902 Fred M. Locke catalog, copy of a 1900 photograph of the Fred M. Locke insulator factory in Victor, N.Y., and copy of a 1904 photograph of the Locke display at the St. Louis World's Fair. The reprints were made from catalogs that are one-of-a-kind. The Lima catalog was just recently discovered. Both of the photographs were made from the original photograph, and they can be found in Brent Mills' book, Porcelain Insulators and How They Grew, which was published in 1970. 

I purchased the following two original photographs at the 1987 Central Regional Insulator Show in Pearland, Texas. They were published in 1972 in the book, Porcelain Insulators Photographed & Priced, by Frances M. Terrill. At that time, it was not known that this was the top shell of M-4600. Note the roughly pebble top surface and the thirteen concentric rings.

M-4600 Top Shell

M-4600 Top Shell showing 13 rings...

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ON THE COVER:

This month's cover has a beautiful photograph on it and deserves to be seen on a white piece of paper to fully appreciate these great multipart porcelains. The picture was taken by Bill Rohde of Williams, California. The crossarm has two M-4415's. The one on the left has 6 ridges under the top skirt and the one on the right has 10 ridges. The piece on top is an M-3955. The pole is no longer in service. The M-4415 with 6 ridges is a nice yellow color. The M3955 on top had a nice light middle skirt.