On December 27th and December 28th I visited the AT&T Archives to see what information was available on insulators. I will summarize my findings below. 

A letter from the Brookfield Glass Company dated 4/5/09 stated that they had successfully completed experimental work on the 'Storrer' insulator and made first shipments of them a week earlier. A separate document states they were being tested in California. The Stoner insulator is CD 211, the Brookfield No Leak. The patent I saw showed a metal attachment on the bottom, not glass.

From documentation I have viewed, from 1909-1914 considerable effort was being made to produce an improved double petticoat insulator. Requirements were sent to both Brookfield and Hemingray to produce a satisfactory insulator.

I found a series of letters and lab reports from the period 1909 to 1910 on the request for the development of a new standard insulator. Hemingray and Brookfield were both working with AT&T to develop the new standard insulator.

From blueprints and photographs of test results I have viewed, the Hemingray CD 155.6 (possibly?), CD 157 and CD 169 were sent by Hemingray, and Brookfield sent CD 153 (possibly) and CD 169.5. Brookfield also submitted a proposed design dated 10/18/10 which is the CD 157. The skirt is convex whereas the Hemingray is more of a straight line. Stress tests found problems with these designs. Later it appears that the CD 152 was eventually designed and selected. 

AT&T rejected the Barclay insulator because of the additional cost of $2.00 per thousand (insulators of that size were going for $30.00 per thousand at that time) to pay royalties to John C. Barclay for the patent. They also said it was not unlike the CD 110.5 and CD 110.6 of which they saw no real advantages in using. Brookfield sent AT&T a CD 110.5 or CD 110.6 sample and in an internal memo, AT&T references it by the patent dates. The archives actually had a CD 110.6 mixed up in a box of CD 129 and CD 203 Kerrs. I don't know if it was the one Brookfield sent but it was a CD 110.6! After my visit I looked at page 51 of Volume 1 of the Insulators - A History and Guide to North American Glass Pintype Insulators, by John and Carol McDougald and saw a reference that Brookfield may have offered the CD 110.5 or CD 110.6. Now knowing this, I need to revisit that file and read it more closely.

Hemingray proposed a transposition insulator shorter than the regular CD 196 to AT&T. The blueprint was sent to AT&T for approval. The blueprint is dated 10/24/10 and is signed by Ralph Hemingray on the back and looks remarkably similar to CD 196.5.

In a series of letters from Western Electric to various Bell Companies and Western Union, beginning in February 21, 1910 and continuing through November 2, 1910, an effort was made to save $.50 per thousand on the cost insulators by omitting custom embossings with phone company names on them. In Massachusetts it was not possible because the Acts of Massachusetts section 17 stated that "Such person or corporation shall, in cities, affix at the point of support at which any wire or cable containing wires provided for in the preceding section is attached, a tag or mark distinctly designating the owner or user of such wire or cable." This may explain why insulators used in that part of the country are embossed with phone company names. (New England Telephone and Telegraph, Southern Massachusetts Telephone Company, Fall River Police Signal, City Fire Alarm, etc.) I don't know if laws like this existed in other states, but it doesn't appear so.

In a letter dated 3/2/12, the Cumberland Telephone & Telegraph Company in Nashville, Tennessee, (which became part of Southern Bell on July 1, 1926) was having a problem with carbon coating on insulators. Replaced insulators were saved and an economical way of cleaning them was sought. They cleaned them with a solution of caustic acid, muriatic acid and water. It was claimed to take between 2 and 5 minutes and at a cost of .25 per thousand.

In a letter from Brookfield dated 2/5/14, Brookfield agreed to furnish Western Electric with 2 insulator moulds for the price of $80.00. The price included samples of insulators and necessary time for testing. 

In the February 1995 issue of Crown Jewels of the Wire on page 12 there is a picture of a man climbing an experimental telephone pole. I viewed the original picture (97045) and it was taken on 12/17/41 in Chester, New Jersey at a Bell Laboratories test facility. All of the insulators are made by Whitall Tatum.

The CD 154 insulators on the bottom row are too dark to be purple so I suspect they are amber. The second and third row from the bottom are straw or clear. The 4th and 5th rows from the bottom appear to be CD 128. The 6th row from the bottom are CD 176. The top row is blurry in the original picture but they appear to be CD 106. 

There were numerous pictures of the AT&T bridle wire insulator along with accompanying documentation. However I never looked at them because I thought it was a scientific use insulator that was unrelated to what I was interested in. It is referenced on page 143 of Volume 1 of the Insulators - A History and Guide to North American Glass Pintype Insulators by John and Carol McDougald. 

A 16 page catalog was on file entitled "Some Interesting Facts about Hemingray Glass Insulators". It was undated but the letter accompanying it from Hemingray was dated 4/9/13.

In a letter from The Locke Insulator Company dated 4/3/08, the increasing prices of all glass insulators was called into question. Locke was trying to compete by offering what it called a superior insulator at a lower price. So did Thomas. In some Western Electric catalogs it appears as though Locke was somewhat successful because porcelain insulators made by Locke are pictured.

I need to view them again, but Western Electric catalogs from 1910 to 1915 showed either Brookfield or Hemingray insulators depending on the year.

I saw numerous interesting pictures of damage to telephone poles with multiple crossarms from hurricanes, tornadoes and ice storms.

I saw numerous other Western Electric inventions including switchboards, telephones, sewing machines, electric fans, vacuum tubes, etc.

I was able to hold the original patent issued to Alexander Graham Bell for the Telephone.

The archives had the following mint condition early insulator collector books on file: 

Lynn R. Stuart - Stuart's Insulator Guide 1970 Revised 2nd Edition; 
James. L. Hill - An Insulator Book for the Advanced Collector 1971 Revised Edition; 
Tibbits Volume 3; 
Milholland Reference Book #2; 
1972 Milholland Price List; 
Cranfill & Kareofelas Book 1 Revised;
The Locke Story September 1947. 

I welcome any feedback or questions about my visit.

David R. Wiecek, N.I.A. #3225 drw@attmail.com