December 1978 Porcelain Insulator News

Recently I found two guy wire insulators with a marking that I have not seen before. It has a large "O" stamped in light yellow ink on the bottom of the insulator. The insulators are brown, 2-1/2" by 3-1/2", circular bottom firing rest.

The marking could be the number "0" or the letter "O". If it is the letter "O", could you tell me what company made it? Any other info would be helpful.

Conventional strain insulators such as this are nearly universally cataloged in the 500-520 number series, and this is the #502 size. The "0" would appear to have nothing to do with the size. If it's a manufacturing company designation, no telling which company. Ohio Brass Co. always used their regular O-B logo on strains, and they don't use underglaze markings on poleline items as far as I know. Maybe one of our readers can identify this marking for us.

My sister was at a flea market and got me some porcelain insulators. Two of them are U-151 with a small metal rod (1/4" tall) leaded into the insulator's top. One is a brown mo-name, and the other one is white with a CP marking as sketched.

Could you please identify what these insulators were used for with this leaded top, and also the name of the manufacturer?
Dave Brown
Exeter, Cal.

The monogram-CP marking is Canadian Porcelain Co. I've seen these gadgets before but never did know what their special use was. Maybe one of our Canadian insulator buffs can help us out with the answer.

On page 33 of the September 1978 issue of CJ there is a photo of Ronny Rofe leaning on a huge porcelain insulator. My father and I would like to know if you have any info on it -- the U- number, manufacturer, vintage, value. Could this insulator mould be a changed Pyrex CD-331?
Dave Kolbe
Manchester, Conn.

I agree, it is huge -- about twice the size of any Pyrex design. This is at least a 4-part (if not 5-part) cemented- together multipart, and there are hundreds (if not over a thousand) of different multiparts as made by a dozen manufacturers over an 80-year period. No one ever has made, or ever will make, a style chart for all these large multis.

I wouldn't care to guess from the magazine photo the manufacturer or its vintage. The only way to determine the value of such insulators is to ask yourself what you'd pay to get one like it, or what you'd take for one if you wanted to sell it. The range of answers from one collector to another would vary all the way from zero to "bundles".

There is no relation whatsoever to manufacturers of porcelain and glass insulators. Similarly, our newspaper doesn't have facilities for brewing beer, and our brewery doesn't print newspapers. They are completely different animals.

Enclosed is a sketch of an unusual (to me at least) porcelain insulator. [Marking is LAPP/1930 plus Lapp monogram.] Is this piece a fairly common insulator and, of course, do you know its value?

In general, I don't see too many Lapp insulators around. Is this because they didn't make many, or are most of them still in use?
Adolf Schimpf
Dover, N.J.

Your Lapp item is U-403A, and we list the consensus value on these at $8 to $12 in the book, but with a notation that these prices prevail in the west and might be a bit lower in the east where these were used and are found.

I don't really know how common these and similar styles of cable insulators are, but l'd say they are not common in collector circles. The ones that have come our way have usually been from batches liberated by eastern people who have some pull with utility company operations.

You are correct that Lapp pin types are not nearly as common as those from the other larger companies. Lapp always made pin types, but their emphasis was on suspension insulators and all the many forms of specialty HV porcelains. They even quit making unipart pin types in 1957 and dropped multi-part pin types several years later.

... Secondly, in the 1925 edition of the Keystone Catalog (Coal Edition), a mining catalog, I found an ad for The Cooke-Wilson Electrical Supply Company -- addresses of Pittsburgh, Pa., Charleston, W. Va.; Athens, Ga.

Among the many mining products (all electrical in nature) was "Insulators: All kinds." There was also a photo of their Catalog #4, a thick book. Apparently this 1925 cataloging jibes with the dates (1914-1932) you give for American Porcelain Company being in business....
Matt Grayson
Roslyn, N.Y.

Many thanks to Matt for shooting down another unattributed marking on pin types. The sole specimen of a pin type with this marking is a U-98 mine insulator found by Carl Lensce in 1973 at the old site of the defunct American Porcelain Co. in East Liverpool, Ohio. (Jerry Turner take note: When this specimen was found, my crystal ball said the initials in the marking stood for "Electrical Supply Co.")

Lew Hohn (Rochester, NY) acquired this small foreign-style insulator from a house in Victor, N.Y., and it was allegedly made at the Victor plant many years ago. It's white, unmarked, no firing rest, normal foreign-size 1/2" pin hole. (Locke did manufacture and catalog for export some small foreign styles in the 1910-1920 period, and possibly later.)

Also found with this specimen was a "mushroom" style Sim U-357 (smaller, 4-1/8" x 3-7/8"), and it looks like a characteristic Locke product.

While vacationing in the midwest, Lew saw some yellow insulators coming into a town and a few inside the town. Through a lineman there, he managed to get one, and it's a Thomas U-668 -- the "brightest yellow" Lew has ever seen on any insulator before.

I have a couple of questions about your First Edition of Porcelain Insulators Guide Book.

In Appendix A (pages 188-197) you tabulate for each U- number the Base TV and the "Confirmed Manufacturer". What I'd like to know is, when you list a certain company under the confirmed manufacturer section, does this mean you have seen specimens marked with the name or trademark of that company, or is it that you had seen that shape (U- #) in that particular company's catalog?

Also, if there is no confirmed manufacturer listed, does that mean that specimens for that U- number are unmarked? I realize that many new markings etc. have been discovered since, but I find this Appendix very helpful.
David Bethman
Bellingham, Wash.

Glad you asked! Others have asked roughly the same question a number of times, so here's the answer.

The original pricing system required a tabulation of all the U- numbers with a Base TV (Trade Value), and then this base value was adjusted upwards or downwards for rarer markings and colors, insulator condition, etc. The column in this long tabulation headed "Confirmed manufacturer" was just added as an informational bonus. It seemed a shame not to advise collectors of what companies made some of the exotic shapes, since many of these are not marked but were shown in catalogs.

The data for this "Confirmed manufacturer" column in the tabulation came directly from my master drawing sheets for each U- number. Generally it shows which company cataloged that style. But the style chart includes several hundreds of shapes which we've found in specimens but which never showed up in the catalogs that I had seen to that time. A "Confirmed manufacturer" was shown for these if the specimens were marked; otherwise, the column shows a blank space for that style.

Everyone agrees with you that the tabulation was very useful, especially to show the manufacturer of styles made by only one company and which were never seen with a marking. We had a problem though, in that we had a small flood of mail from collectors wishing to report that they had some ordinary style with a marking not shown for that style in the tabulation. Trying to tabulate all such data for ordinary styles would be an endless job and also of questionable value in the end. I have never made any attempt to record all the various companies that made given styles.

This tabulation was dropped from the Second Edition of the book, primarily because a new pricing method merely indicates prices for all the specific insulators worthy of mention. At the same time, we naturally lost these "Confirmed manufacturer" data. Newer collectors without the old book may now wonder who made styles such as the U-395 Mickey Mouse (Pittsburg), but at least the aforementioned flow of mail about manufacturers of the common styles abated.

Most of the worthwhile information on manufacturer of various styles concerned the oddball items made by Pittsburg High Voltage, but we have since learned that Pittsburg manufacturing methods were so uniquely different as to allow us to identify their insulators in most cases by inspection alone. Most collectors specializing in Pittsburg are well informed on this, and we have widely published this information in this column and elsewhere on several occasions,

Matt Grayson (Roslyn, NY) recently sent an advertisement clipped from "Transrnission and Distribution" magazine which showed a complete line of wet process, high-voltage insulators being marketed by Porcelain Products Co., Carey, Ohio. This company is a wholly owned subsidiary of the Clarken Company of St. Louis, Mo., and the Carey plant is the old dry process porcelain plant formerly owned by the A. B. Chance Company. Chance sold the Carey plant to Clarken July 1, 1963.

To learn more about this development, I wrote to Mr. Rea Guthridge, president of Porcelain Products Co., and his reply was, in part:

"No there isn't a new manufacturer of pin type insul ators. In September of 1975 Porcelain Products Co. bought Knox Porcelain Corp. We incorporated Knox items into the product lines sold by representatives. We also started to mark all products with both the and logos. Enclosed is a copy of the catalog section showing the items we are offering for sale.

"Late in '77 or early in '78 we started to make pintype insulators on a new Wahl press system. This necessitated new tools, and that's the first radical change made in the manufacturing method...."

No, but yes! We do technically consider this a "new manufacturer" event for pin types, since the actual ownership (corporate or company name) and markings used are of dominant interest to us.

Mr. Guthridge was not specific as to the use of two separate markings versus a combination marking, or as to the type of marking method. I'm guessing that it means two different marking stamps, and that these are underglaze types as were used in the Knoxville plant at that time. If you collect specimens from all possible "manufacturers", here's something new for you to chase after.

George Hanson (Columbia Falls, Mont.) sent us a clipping from the Montana Rural Electric News which had some news on recent developments in high strength porcelain insulators. The work is being sponsored by the Electric Power Research Institute (EPRI) which is supported by over 500 of the nation's electric utilities.

McGraw-Edison Company more than doubled the strength of standard electrical porcelain by reducing the porosity to make the body material more compact and by closely controlling the firing process.

Gould Inc. (Victor, NY) more than doubled the strength of high alumina porcelains by altering the composition and by improving the methods of mixing, forming and firing.

These developments could lead to higher ratings for given designs or to higher safety factors under current ratings. Manufacturers will soon begin procuring equipment for making the improved insulators, and production should be under way within two years.

(I believe these developments will probably have no major effects on the visible appearance of ordinary pin types, since their sizes are mostly a function of the voltage rating and not a function of their mechanical strength. JT)

Emma Almeida (Shrewsbury, Mass.) reported more old wiring cleats and knobs she has acquired, but one was a real eye opener -- the first report of a "Cartwright Cleat" as shown here. The split name CARTW / RIGHT appears on the other side between the wire holes.

As shown in my book Electrical Porcelain, this 1-6-91 patent is #444,317, Electric-wire insulating-cleat, J. S. Potter and D. C. Cartwright, Boston, Mass. This is a one-piece cleat with tapered holes for the conductors which are to be held in place with small wedges in each hole.

This is a real museum classic, one of the earliest patents for a porcelain wiring cleat. Even though it was necessary to string the wires through the holes of all these cleats, this wasn't bad for a first try. A succession of patents followed for cleats not requiring this tedious installation process.

It is unthinkable that anyone would have used one of these Cartwright cleats after the very practical two-piece cleats were on the market only two years later. Unless you happen onto a standing building with the original 1890's wiring or hit it lucky in the right dump, don't expect to ever find an early rarity such as this.

Here are some more interesting items reported by Lew Hohn (Rochester, NY). He found these insulator "advertiser" items at various flea markets in his area.

The first one is this light tan pipe tray with the embossed (raised) markings for Victor insulators, Inc. (1935-1953), Victor, N.Y. Tray and marking are both drawn 1/2-size.

Here's another "advertiser" from Victor insulators, Inc. You probably got your soup or ice cream served in this bowl and discovered the commemorative marking when you ate your way to the bottom of the bowl.

There's little doubt that this company was one of the most prolific issuers of all sorts of advertiser items. (The bowl is drawn 1/2-size.)