In May 1997 Crown Jewels of the Wire, we discussed the Hewlett suspension insulator and the Ohio Brass link strain insulator. Both styles of O-B link strain were shown on page 24. The older version with the flat sides and relatively sharp flange edges was shown in the 1912 O-B catalog and the more common rounded version we call the "hog liver" or "pork liver" insulator was shown in the 1919 O-B catalog. I got one of each type at the Rosemont National show last July. The photograph below shows both versions together and each has the embossed O-B marking. The "pork liver" insulator has a typical black / tan mottled O-B glaze from the 1920's-1930's. The older version has a rather dark purplish mahogany glaze and is very shiny. The two holes were carved out straight through rather than curved as in the Hewlett design. The sides are crude as though someone carved away excess clay all the way around. Note that there is a relatively sharp drip edge on the top and bottom of the flat sides that extends away from the body of the insulator. There are two flat areas on the bottom drip edge, which were unglazed and acted as the firing rest.

Two Ohio Brass link strain insulators: "pork liver" on left (7-1/2" in
 diameter) and earlier version on right (7-1/4" in diameter and 2" flat sides).

Ed Sewall, Mike Spadafora, and Robin Harrison (NIA #1309) have made several trips in the mountains east of Seattle at Steven's Pass where they have found various broken early O-B link strain insulators along an old trolley line that was part of the catenary system. They found a couple of early O-B link strain insulators that had a beautiful orange glaze! This glaze color is the very earliest of O-B glazes indicating the insulator was made soon after the Akron High Potential Porcelain Co. was taken over by Ohio Brass in 1907. Remember the Priestley patent for this insulator style was applied for in December 1910 (granted on October 1, 1912) so the orange-glazed insulators were made very near that time period.

Older version of the O-B link strain with beautiful orange glaze.

Ed, Mike, and Robin also found another O-B insulator similar to the link strain that was used in vertical suspension service on the catenary system. Unlike the older link strain which has two drip edges on the 2" flat outer surface, this insulator has only one drip edge that, when mounted vertically, hangs down like an outer petticoat (just like on the older link strain). The top outer surface is rounded with the body of the insulator. This insulator was not shown in any of the Ohio Brass catalogs that I have but must be of the same vintage as the other O-B link strains.

Odd type of O-B vertical suspension with only one drip edge.

I also got a couple of other unusual insulators at the Rosemont National show that are similar to the Hewlett and O-B link strains. The first one is most like the "fish-tail" Hewlett except the outer edge is slightly convex (curved out). The outer edge surface of the 8" diameter wheel-shaped insulator is 2-3/4" wide. The insulator has curved interlocking holes similar to the Hewlett (not straight through like the O-B link strains). The glaze color is metallic tan with a few blotches of black. This rather early looking insulator has a sanded spot on the curved outer surface of the ring which was used as a firing rest to fire the insulator vertically in the wheel position. Oddly, the firing surface was not flat.

I didn't see this style of insulator in any of my catalogs while researching the May PIN article. Quite by accident I found this insulator described in my Pittsburg Export Catalog No. 20 (circa 1920). A copy of that catalog page is reproduced here. The only difference is the catalog shows the outer surface to be 3" compared to 2-3/4" on the specimen. We know that Pittsburg produced more styles than any other porcelain manufacturer and they copied popular glass and porcelain styles made by other companies. They evidently did not pass up the chance to copy the Hewlett "fish tail" strain insulator. However, Pittsburg may have had second thoughts about copying the popular Hewlett suspension insulator that was being manufactured by General Electric, Thomas, and Locke. Then again, the Hewlett popularity was mostly after Westinghouse took over the Pittsburg factory in 1922 and, too, Pittsburg offered several cap and pin suspension insulator styles which were easier to make.

Pittsburg 8" diameter strain insulator.

The second unusual strain insulator is only 6" in diameter. It is shaped like a ball with a 1" ring around it and has two curved interlocking holes like the Hewlett. The glaze color is mahogany with blotches of mustard indicative of Thomas manufacture in the early 1910' s. I could not find this insulator in Thomas catalogs from 1915, 1920 or any other year.

Early Thomas 6" strain insulator (left) and 
7-1/2" Thomas "fish tail" strain insulator.

Back to the lines around Steven's Pass east of Seattle, Ed, Robin and Mike have also found numerous broken M-3070's that were cemented on Lee pins. Mike found a piece of a broken crown with the marking, "LIMA, N.Y." The glaze color and other characteristics indicated, too, that these were Lima manufacture. After many trips searching the line they managed to find three or four whole M-3070's in good condition but none of them have the Lima marking. In addition, Mike found the two top unglazed portions of the middle shell that had the following 1-3/16" diameter black ink stamp. 

There will be more details on their hunts in the mountains east of Seattle latter this year with an article that will appear in Crown Jewels of the Wire. (See page 5 this issue, The General Electric Company Porcelain Factory and the U-701 by Ed Sewall.

M-3070 N-N Lima found near Steven's Pass east of Seattle.

Various Lee pins was taken from the 1910 Locke catalog.