Questions Answered by N. R. Woodward
Author of The Glass Insulator in America and originator of C.D. #'s (Consolidated Design Numbers)

Reprinted from "INSULATORS - Crown Jewels of the Wire", May 1978, page 10

Wayne L. Barnes, Hamler, Ohio, writes: I would like to ask about the insulator pictured below.

I wrote the Milhollands about it a while back, and I told them it was a star CD 113 insulator. She told me I might have mistaken it for a CD 112.

Well, this time I drew a picture of it. As you can see, it is a CD 113. There is just one star on the front. (The S.B. stands for smooth base.

I just want to know if it was left out of Milholland's book by mistake, or what (3rd Revision).

Please let me know what you find out. I don't know if it is rare or common.

My wife and I were at a flea market recently, and I purchased an insulator I cannot locate in Milholland's 3rd Revision. It is a C.D. 121 Toll insulator, inscribed as follows: F-HEMINGRAY B-PATENT MAY 2 1893. The color is aqua, and there is a considerable amount of "snow" in the glass. It also has sharp drip points.

Please send any information possible about this insulator that you may find. It would be very much appreciated.

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In reply to Wayne L. Barnes: Yes, of course, you have a Star CD #113. I've had this item in my collection for years. As to why it was left out of Milholland's book, I can't say; but I can say that they aren't plentiful and make an addition to your Star line of which you can be proud. The Star CD #112 is far more common.

As you know, the CD #131 style was developed for the early telephone "long lines", or toll lines, as they spread over the country in the 1890's and early part of this century. Most of them were embossed AM. TEL. & TEL. CO.; but you have one of the early Hemingrays. This item, embossed as you describe, isn't rare; but it's a tough one to find in mint condition.

Dean Meneilley, Belleville, Ontario, Canada, states: One insulator you may be able to help me with is a C.D. 154 Hemingray 42, in a just off clear color (line 1714). This insulator lists as $95.00. I cannot see why it is just so much. Maybe you can help me?

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In reply to Dean Meneilley: The item listed in line 1714, 1976 Milholland Price List, is described as "like E14-B". That indicates that it is of a special glass, probably fused silica, similar to the experimental CD #128 that were embossed E14-B. Since I haven't seen this item, I can't make a first-hand statement; but a Hemingray-42 made of that type of glass would not be a regular production item and would undoubtedly be rare.

From Michael T. Vander Horst, Napolian, Ohio: I have found a CD 145 Beehive that I can't find in Milholland's book. The description is: Brookfield--F--Crown Arc. --W. Brookfield/ 45 Cliff St/N.Y.--B--Crown Side Number (20)/PATD NOV 13th 1883/FEB 12th 1884--M.L.O.D.--Inner skirt has 4 equal spaced small sharp drip points--Green.

The description is almost the same as Line 1419 in Milholland's 1976 Price Guide. Do you, or any of your readers, have an insulator like this, or know the value of it?

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In reply to Michael T. Vander Horst: Your Brookfield CD #145 isn't particularly scarce. It comes from a common mold group. Of course, as with any of these Brookfields, you might look a long time before you found one with a particular shop number (yours is 20); but I've seen this one quite often. Things to look for on these are sharp embossing and unusual color. The discouraging thing about the crown-embossed CD #145 Brookfields is that so many have very weak, almost illegible embossing.

Carolyn Theesen, Lawton, Oklahoma, has five questions: 1) On a Whitall Tatum Co No 1, what does the under Tatum stand for? 2) Also in Tatum, some of the T's are like this and some are like this . Is this of any significance? 3) Could you please tell me what S.C.A. on insulators stands for? 4) I have about 15 Armstrong DP 1 insulators, but only one has Armstrong's written in slanted lettering with the s, and all the others only have Armstrong with printed letters. Do you have an answer for this one? 5) Also, on the back of the Armstrong DP 1 are numbers such as 7-68 57 61 and so on. What do these stand for?

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In reply to Carolyn Theesen: On the Whitall Tatum insulator that you describe, 4 is the mold number. When they make up a set of molds, they number them serially. That gives them an immediate identification of the mold at fault in case insulators come off the press with a defect. A mold set may consist of any number of molds, depending on how many insulators of that style were being made at the time.

The variation in the letter T would have no significance. The differing styles could have been made by different mold engravers.

The letters C.S.A. on CD #128 indicate that the insulator was designed for Carrier service and for use on a Steel pin. We are not so sure of the third letter; but it seems to have been added to identify a specific mold group. Later insulators, with extremely minor variations, are embossed C.S.C. and C.S.O.

The Armstrong's DP 1 with the slanted letters were last made in the 1952 mold set. Subsequent mold sets were engraved with the circled A and printed letters. Both were used for some years and are common.

The small numbers on the Armstrong insulators are the mold and date codes. The numbers 57 61 would indicate mold number 57 of the 1961 mold set. If there are dots after the 61, add one year per dot. For example, 57 61::: would indicate that the insulator was made in 1967.

Bob Berry, Jr., of Bethlehem, Pennsylvania, writes: I have just acquired some insulators I cannot find in Milholland's.

The first one looks like some sort of electric fence insulator. I would appreciate any information as to it's use or rarity. It has a pin hole about the size of Surge insulators, and it is embossed IN-56 on the front and has Owens Illinois trademark over 18-45 on the back.

The second insulator is a C.D. 124 embossed:
F- Hemingray / No. 13
B- Patent / May 2 1893

It is definitely C.D. 124, not 124.2 as listed. It is absolutely identical with the usual No. 4 of this style, except for the 13. Under the 13 there is evidence of a blot-out. Perhaps the 4 was blotted out and the 13 put in.

The last insulator is C.D. 252 No. 2 Cable in ice green.  Have many of these been found?

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In reply to Bob Berry, Jr.: Your IN-56 is only part of an insulator. They were never sold with just the glass, but were fitted with a steel pin which was cemented in with metallic cement. The pin has lag screw threads so these little insulators could be attached to any pole, tree, or wood building. They were used by the military in the 1940's, and later many showed up in surplus stores. They were subsequently used on private rural phone lines to some extent and very possibly, as you suggest, for electric fences.

No. 13 was the last number used for CD #124. Not so many were made during those later years, and the ones with No. 13 are much more scarce. You are probably entirely correct about a 4 having been covered in the mold and replaced with the 13.

The CD #252 No. 2 CABLE you describe may be Canadian. Dominion made some of these embossed exactly as the Brookfields were, but of the typical light green and straw Dominion colors.

Fred A. Escher, Sun Prairie, Wisconsin, writes: Enclosed is a picture of two insulators I obtained at a recent bottle show here in Wisconsin. I cannot find any information on these two insulators, so wonder if you can help out with a CD number, manufacturer and approximate value.

The insulators are 2.7 inches across the base, 4.2 inches high, with the center of the wire groove being 2.5 inches from the base. Both insulators have a 1/2 bar, a 3/4 bar and then a close grouped series of four 1 inch (approximately) bars on the inside of the skirt. There are no other markings. They are light blue or aqua in color, and the only physical difference is that the insulator on the left has about a 1/8 inch rise in the glass right under the wire groove.

Any information you can give on these insulators would be appreciated.

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In reply to Fred Escher: Your two unembossed CD #126.3 American Union Pattern insulators have been found occasionally on old lines, mostly in the Midwest. Nothing whatever is known of their origin. They would probably be between 80 and 100 years old; and chance for a positive identification seems small.

From John Palyo, Flushing, New York: My son John Vincent, age ten, has found some insulators this past year that are not listed in Mr. Milholland's ref. book or the new 1977 price list. I hope you or the readers of "Crown Jewels" can provide some information concerning these insulators as to scarcity and value. They are as follows:

1. CD 102 front/Brookfield, Back/New York, crown top backward #1 , color Yellow Green.

2. CD 102, also a Brookfield, about 3/16" shorter than the rest of the Brookfield CD 102's we have. The color is almost an Ice Blue. The embossing is very large and bold on both sides, with Brookfield on the front and N.Y. on the back, a backward number on the crown with a spot of glass on each side of it. I will try to draw the crown top.

3. CD 121 A.T. & T. Co. in Green with both a Roman numeral and a number on top of the crown, partially double embossed on an angle.

4. CD 164 Whitall Tatum No 5 in Clear, the embossing or it as follows:

The two dots on the top of the triangle are small, and two dots on the side are large. But what really drew our attention is the mold line. It comes up the side on both sides to about 3/4" above the wire groove, then completely circles the dome.

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In reply to John Palyo: The CD #102 Brookfields were made in such great numbers for about 40 years that the variety is almost without limit. They vary in size, embossing, and quite a range of markings were used as shop numbers. Since these numbers were for the identification of the source of the insulators as they were taken from the annealing lehr, and nothing further, they were an internal code at the factory, and cannot be ascribed a specific meaning beyond that. Shop markings commonly seen on CD #102 include numbers from 1 to 17; X0, X1 and X2; and letters A, B, C and D. Added to that is the consideration that much colored glass cullet was used at the Old Bridge plant. It becomes obvious that no list, at least of the scope presently available, will be anywhere near complete in exact descriptions of the Brookfield CD #102. While most of them have no special value, they are fascinating and beautiful to collect. And you can always be assured of finding one that is in some way different.

The A.T. & T. Co. CD #121 is also a Brookfield product and has the typical Brookfield shop number on the crown. The "double embossing" happens as the melted glass folds into the mold, and a surface will rest momentarily against the engraving and pick up a partial embossing as it starts to cool at the surface, before settling a fraction of a second later into its final position in the mold.

Your Whitall Tatum No. 5 was made in mold #6, in 1941, and the four dots around the triangle indicate fourth quarter production. So your insulator was made about the time the United States entered World War II.

The mold line position you mention is quite common on Whitall Tatum insulators. Quite often they show a mold line between the crown and mold halves at a point above the upper wire groove lip, instead of on the crest of the lip as is more common. Perhaps an old time mold maker could tell us why this was done; but one effect would be to eliminate the possibility of a sharp ridge on the lip, as happened with some earlier insulators.