July 2002 Porcelain Insulator News

Nearly all that has been discussed in Porcelain Insulator News since Jack Tod started this column in 1972 has been about pin-type porcelain insulators. There are many other interesting porcelain insulators such as standard porcelain. This category is composed primarily of knobs and spools as the direct result of the founding of the Underwriters' Laboratories, Inc. in 1894 by National Board of Fire Underwriters to formulate safety standards for the industry. Prior to that time, wood was commonly used for house wiring attachments in the form of knobs, cleats, fuse holders, switches, lamp sockets, ceiling rosettes, etc. You can imagine the fire hazard wood posed. By 1891, insurance companies would not tolerate the use of wooden wiring insulators because of the fire hazard. The new UL fire codes brought an abrupt end to the use of wood and pushed the porcelain industry to the forefront for all electrical uses.

Many small electrical porcelain companies sprung up in the early 1890's to make wiring insulators. The National Electrical Code was published in 1897, which included standards for electrical porcelain insulators used for "over-surface" wiring. This is common house wiring that ran over rafters and through studs and walls. Initially the code was set up for two-wire cleats and tubes. Then a vast array of standard porcelain in the form of spools and knobs was numbered from 00 to 62. Additional styles were added such as No. 5-1/2 and No. 9-1/2. Any wiring insulator outside the standard styles was referred to as "specialty porcelain". Many patents cover cleats, tubes, and other specialty porcelain designs. All of this is covered in great detail in Jack Tod's masterfully researched book, The History of the Electrical Porcelain Industry in the United States. It was published in 1977 and a few copies are still available for purchase (www.r-infinity.com) .

The subject of this month's PIN is one small category of electrical wiring insulators - wall tubes, and, more specifically, "glazed" wall tubes. Most wall tubes were used to safely pass house wiring through rafters, studs, or walls. As stated before, many small companies sprung up to make porcelain wiring insulators. All of these small insulators were glazed, so it was a natural progression to glaze wall tubes. Many of the earliest wall tubes were not actually made of porcelain. They were made from a form of pottery that was inherently brittle. The glaze acted to make the pottery stronger and more durable and also improved the electrical characteristics, which wasn't all that important for house wiring. Newer massed-produced wall tubes were made of unglazed porcelain and, as such, will not be covered in this discussion in any great detail. Unglazed wall tubes have little or no value to the collector unless a desirable marking is associated with them such as "P&S". Even then, values remain quite low. Pass & Seymour made the first wall tubes out of porcelain starting around 1892 and continued using this material for many years. Most of the ones I have seen have been unglazed.

One of the earliest if not the first manufacturers of glazed wall tubes was the Akron Smoking Pipe Co. (1890-1919) located at 3775 Mogadore Road in Mogadore, OH. It started out as the E. R. Merrill Co., which produced "Ohio stoneware and clay specialties". On September 3, 1890, the company was incorporated as The Akron Smoking Pipe Co. (ASPCo) with offices on Falor Street in Akron, OH just west of Main Street in the same building as the Diamond Match Co. It controlled the clay smoking pipe business of five other companies with directors who owned the other companies.

ASPCo started making electrical porcelain in the 1895. In 1906, the company manufactured the first third rail insulators used in the U.S., which went to the N.Y. Central Railroad. It produced all the original insulators for the West Shore Line of the same railroad. Akron Smoking Pipe Co. became Mogadore Insulator Co. in 1920 and The Akron Porcelain Co. in 1929 located in Kenmore, OH. In 1984, the company name was changed to The Akron Porcelain & Plastics Co. with plant located on Cory Avenue in Akron, OH. In 1988, they opened a second plant in Barberton, OH and the company is still in business after more than 110 years.

The logo is from the book, A Centennial History Molding a Legacy: The Akron Porcelain & Plastics Co., by Stephen H. Paschen (courtesy of Mike Lewis, Pres.)

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CLAY AND PORCELAIN GOODS.

The Akron Smoking Pipe: Company, of Mogadore, O., are extensively engaged in the manufacture of all kinds of white and brown clay and porcelain insulators, being a new department which this company have added to their business. They make insulators in a variety of sizes running from one to twenty-tour inches. with diameter from 5-16 to 1-3/4 inches. They also manufacture in the three materials two styles of cleats which are designed to hold two wires, a complete line of knobs suitable for all wiring purposes. such as telephone, telegraph, street railway purposes, etc., and a line of specialties. They solicit any specialty that is used In quantities that can be manufactured either of porcelain or clay material, such as fuse boxes. switchboard plates; etc.

The article above was found in the September 2, 1896 Issue of The Electrical Engineer.

The companies shown below also began making electrical porcelain in the 1890's. Dates are years the company was in business or years at that location:

There are many other porcelain companies that made standard porcelain and specialty porcelain and some of the ones mentioned above may not have made glazed wall tubes. Not much is known about glazed wall tubes because many are unmarked, and it was a cheap item hidden away in walls for a century or more. Glazed pottery tubes were a standard until just after 1900 when manufactures began to offer unglazed porcelain tubes at a much lower price. Unglazed porcelain tubes were probably easier to make with new modern machinery and eliminated the troublesome fusing of the glazed tube to the firing tray and resulting crude-looking irregular glazes that make glazed tubes attractive for collectors. Porcelain tubes could be ordered fully glazed, too. The 1902 Central Electric Co. catalog furnished unglazed porcelain tubes, and you could order them glazed for an additional 50% per 100. A typical unglazed 6" long tube with 1/2" opening was $5.44 per 100. By comparison, the same glazed . "clay" (pottery) tube was $34.24 per 100. The difference in cost quickly moved the customer to the unglazed porcelain tube. By 1912, Central Electric had quit offering pottery tubes and carried only standard unglazed porcelain tubes and glazed porcelain tubes for 50% more. As early as 1903, Brunt offered only unglazed porcelain tubes. You can easily see why it is not easy to find glazed pottery tubes today plus the fact that they are more brittle and tend to break when removing from a wall stud. Pass & Seymour continued to make both unglazed and glazed (50% more) porcelain tubes and never made the inferior pottery tubes. They advertised that you could hammer their tubes in the hole with a wooden mallet.

This advertisement was found in the
Electrical Review dated May 4, 1898.
(courtesy of Bob Stahr)

Very few manufacturers have been identified from glazed tubes in my collection (I don't know of anyone else collecting glazed tubes). The following markings are known:

Here are a few markings on unglazed porcelain tubes that are particularly rare or difficult to find:

I recently acquired a couple of wall tubes on Ebay that have a characteristic early Thomas glaze mottled with dark mustard color. Imperial Porcelain Works was one of the largest producers of cleats and may have also produced wall tubes. The history of the American Marble & Toy Mfg. Co. and Akron Insulator & Marble Co. is sketchy and confusing at this time, but we do know they made glazed tubes. The site of the American Marble and Toy Mfg. Co. was dug a few years ago, and I did acquire a variety of insulators found there including two long tubes (one glazed) with deep incuse mark "A M" on the end of the head and two short unmarked wall tubes with a light blue glaze with sponge-mottled darker blue. A few knobs embossed with "A. I. & M. Co." were also found there, but I don't know if both companies were associated in some way. AI&MCo was consolidated with the Colonial Sign Co. in 1904 and AM&TMCo burned to the ground in 1904. The two companies were located less than two miles from each other (on opposite sides of IH-76).

A sample of small porcelain insulators found during a dig
at the American Marble & Toy Mfg. Co.
Note that the cleat and one nail-knob are embossed A.M. C.

I have several brown tubes made by Akron Insulator & Marble Co. embossed with "A. I. & M. Co." around the square head and one with incuse marking on the tube. There are also a few gray-white glazed tubes embossed "A. M. C." on the length of the tube, but I have not seen a brown tube with this marking. This marking is attributed to American Marble & Toy Mfg. Co. from various insulators found at the dig.

Most "white" tubes have a glaze color that is either gray-white, off-white, or greenish-gray in color. I have only two pure white glazed pottery tubes. Of all the various sizes of tubes offered in catalogs, there must be many other sizes one could find to add to their collection. I mounted most of my collection on dowel rods fixed to a large board. Tubes can be easily added or rearranged by sliding out the dowel. Below is a photo of this set-up and photos of individual tubes. Often markings are difficult to make out entirely, but if you can see a few of the letters, you should be able to identify the complete marking. Adding a new glazed tube is a slow process, which makes it especially rewarding when you do find one.

Collection of glazed and hard-to-find unglazed wall tubes
mounted on wooden dowels attached to a large board.

The large tube at bottom has incuse marking "A. I. & M. Co. ".
The two above it are embossed with that marking around the head.
The tube at the top is embossed "A S P CO" on the tube.

The tube at the top is embossed "A S P CO" around the tube
just below the head. The next tube down has an incuse triangle
marking. The next two have an incuse diamond marking and the
fourth tube is unmarked.

These four tubes are unmarked.
The tube at the top is glazed porcelain and appears to have
been made by R. Thomas & Sons Co. circa 1905-1910.

These five pottery tubes have various gray-white, off-white,
and greenish-white glazes. The one at the top has an incuse
"star". The next one down is embossed "A.I. & M. CO." on the
head. The middle one is embossed "A M C" on the tube.
The last two are unmarked.

Illustration from the 1899 P&S catalog showing a wall
tube inserted in a wall. The patent is for the projections on
the side of the tube that prevents the tube from falling out.
They were made of "Syracuse China" and could be hammered
in with a wooden mallet.

The six glazed pottery tubes above are all unmarked
except for one with an incuse "C" on the head.
(See third tube from the top.)

The five of six tubes above are unglazed porcelain and have
various incuse markings on the tube. The tube at the top is a
pure white glazed pottery tube.