June 2004 Boston Family Album

Crown Jewels this month presents insulators manufactured by, or in some way related to, Boston Bottle Works. Our story extends from page 20 through page 33. Shown on this page: Upper left: CD 136.4 unembossed; upper right: CD 136.4 unembossed; Lower left: 136.5 embossed Boston Bottle Works; lower right: 143.6 embossed Boston Bottle Works.

The CD 136.7 on the right is embossed: PAT. OCT. 15. 1872. It has three segmented threads, and is an especially difficult to locate green color. While similar in appearance to the insulator below, it lacks an inner skirt.
	A previous owner described the insulator to the left as a CD 136.7 / 158 hybrid. It has the dome configuration of the 136.7, but the inner skirt of a 158. The insulator has three segmented threads, and is noticeably shorter than a 158. The dome and wire groove shapes are different than 158's. Like the insulator above, it is embossed only with the 1872 patent date.

Crown Jewels this month presents insulators manufactured by Boston Bottle Works, a glass manufacturer in operation in the 1870's when growth in the telegraph industry was rapidly expanding. Our description of the whole group as "Bostons" is intended to be a method of describing them. In fact, certain styles were produced by glass companies that existed both before and after Boston Bottle. However, the insulators are linked by their peculiar style of manufacture... the patents of inventor Samuel Oakman.

Oakman was granted almost two dozen patents, not all having do to with insulators. But collectors are quite familiar with at least two Oakman patents. The November 13, 1883 patent date found on insulators produced by Brookfield and other companies refers to the invention of the inner skirt. Another Oakman patent copied by many companies is the June 17, 1890 patent for a saddle groove, essential in the development of power insulators.

Less successful, apparently, was Oakman's October 15, 1872 patent for segmented threads. The patent drawing is shown on the opposite page. In volume 1 of the book, Insulators: a History and Guide to North American Glass Pin type Insulators by John and Carol McDougald, the idea behind segmented threads is described as a means to reduce manufacturing costs. With segmented threads, the plunger could be removed without having to unscrew it from the newly formed threads. While that may have saved time in the manufacturing process, it possibly produced an inferior insulator that came unscrewed from the pins easier.

Insulators with segmented threads were never produced in massive numbers, and few seem to have been salvaged by telegraph companies for re-use over time. The result is that the insulators are scarce, with even the most common examples valued at $500 apiece and up.

The Massachusetts Glass Company was formed in 1867 with Samuel Oakman as its president. In 1870, the company built a factory at a location that by 1872 was the home of Boston Bottle Works. In the Boston City Directory, Oakman was listed an an "agent" for Boston Bottle until 1877.

Oakman's threadless designs may have been produced when the company was operating as Massachusetts Glass. He received a patent in 1870 for a "slotted pinhole" design promoted as an improvement over threadless insulators (see color pictures on page 29 and the patent design on page 30).

After Boston Bottle shut down in 1877, a new company sprang up called Bay State Glass Works. Oakman was listed as an agent for Bay State in 1878 & 1879. The company was listed in the Boston City Directory as a manufacturer of insulators.

Two of the rarest Boston's are show above: CD 145.6's in outstanding colors. Both are embossed: BOSTON BOTTLE WORKS PATENT APPLIED FOR. Both have four segmented threads. Below are two CD 158' s. They are also embossed BOSTON BOTTLE WORKS PATENT APPLIED FOR; and also have four segmented threads.

Above are two CD 158.1 insulators embossed CHESTER 104 CENTRE ST. PATENTED. Produced with four segmented threads, these were quite possibly made by Boston Bottle for a telegraph supply company located in New York. Below are two CD 158.2 insulators, both embossed BOSTON BOTTLE WORKS PATENT APL'D FOR. They also have four segmented threads.

Collectors speculate unembossed "Bostons" with segmented threads may have been produced when the company was known as Bay State. That company appears to have closed down in 1879. But Oakman's peculiar style of insulators may still have been in production. A supplier of telegraph equipment, Patrick and Cater, advertised insulators with segmented threads in its 1880 catalog (see ad on opposite page). The style appears to be the CD 136.7.

Among virtues of the segmented thread design described in the ad is the ability of the insulator to form its own threads. Sounds like the company hoped to capture a piece of the market at a time when telegraph companies were upgrading from threadless insulators to threaded. The message seems to be that if you bought this style of insulator you wouldn't have to buy replacement pins. Being made of light colored glass is also described as a benefit, as that was supposed to keep insects from burrowing into the wood pin.

By 1885, Oakman was affiliated with the American Insulator Company in New York City. American Insulator produced fully threaded insulators that used a new generation of patents granted to Oakman. Not shown in this issue is the CD 156.2, an insulator embossed with the 1872 patent for segmented threads but bearing threads like an American Insulator product. Some collectors speculate it was experimentally made by the New York company before Oakman received his 1884 patent for forming threads the" American" way. Another similar oddball is the 728.5 American-looking threadless. Crown Jewels hopes to picture these in a future article about the American Insulator Company.

Ok, so what's up with the CD 158.9? (pages 32 & 33).What was the purpose of that screw top? Some collectors surmise that a wrench-like tool fit on the top of some Boston insulators, allowing the segmented sections to form threads when the insulators were screwed onto previously threadless pins. Others speculate the insulator screwed into something, like the bottom of a crossarm. Some feel there was a glass or metal or wooden cap that fit on the top of the insulator for some purpose. It is known that a patent was granted to a man named A.J. Hauty on January 24, 1893 for a self-tying, screw type insulator similar to the 158.9. However, Boston Bottle Works closed in 1877.

Credits: Photographs by Ray Klingensmith & Carol McDougald. References include: Insulator Price Guide, by John & Carol McDougald, 2003. Insulators, A History and Guide to North American Glass Pintype Insulators, by John & Carol McDougald. Various Pole Top Discoveries auction catalogs, produced by Ray Klingensmith.

Color printing for this and other articles in this issue of Crown Jewels was made possible by a donation from Tommy Bolack.

Insulators manufactured by Boston Bottle Works and related companies have been found over a wide area including Pennsylvania, Connecticut, Ohio, New York, Michigan, Missouri, Georgia and a few other southern states. Broken fragments of Bostons have been found in a mining district in New Mexico. A bottle collector dug a broken CD 158.2 in Arizona.

While found at widely scattered locations, the number of insulators uncovered at anyone site has always been relatively small.

Four more CD 158.2's are shown on this page. But the differences extend beyond color. The two at the top are embossed: BOSTON BOTTLE WORKS PATENT APLD FOR. Embossing for the two at the bottom reads, BOSTON BOTTLE WORKS PATENTED OCT. 15 '72.. All have four segmented threads. This style is nicknamed "Boston barrels".

Even threadless insulators with ties to Boston Bottle were manufactured in an out-of-the-norm manner. The two CD 728.7 above are embossed OAKMAN'S PATENT JULY 26, 1870. They have a slotted pinhole with two slots to more firmly affix the insulator to the pin. The CD 728.8 on the left below used the same concept and is embossed: BOSTON BOTTLE WORKS OAKMAN'S PAT JULY 26, 19870. Below, right, is one of the rarest of all insulators: the CD 796. See page 30 for more information about this unusual design.

One of the hobby's rarest insulators is the CD 796 shown above in the patent drawing for slotted pinholes. The 796 was not designed as a transposition, as it might appear. The "umbrella" over the wire groove was just intended to keep the line wire dry. This insulator is embossed, BOSTON BOTTLE WORKS / NO SOMERVILLE / MASS (skirt) OAKMAN'S JULY 26 '70 / PATENT (base) OAKMAN'S PATENT JULY 26, 1870 (around pin hole).

As a group, Boston Bottle Works insulators are arguably the most valuable "brand name" of insulators in the hobby. Oakman's segmented thread concept just didn't seem to catch on. As a result, very limited numbers of Bostons were made, and extremely few survived of some styles.

The following list is of the insulators pictured in this issue. The value given is either what the insulator sold for in recent years, or what it's value is listed at in McDougald's Price Guide. (Many of the Bostons shown in this issue were also recently sold in the auction described on pages 34 through 37.)

Affectionately called "screwtops", CD 158.9 insulators remain one of the hobby's most enduring mysteries. What were those screw tops used for? While there's been lots of speculation, the exact use is still up for debate. Was there another glass part that screwed on the top? Did the insulator screw into the underside of a crossarm? Whatever the reason, the unusual shape and extreme rarity of the CD 158.9 Bostons has made them aristocrats of the hobby.

This CD 158.9 "Screwtop" in emerald green presently holds the distinction of being the hobby's "most valuable insulator". Embossed BOSTON BOTTLE WORKS PATENT APPLIED FOR, this insulator sold for $35,000 this spring. Previously the highest price paid for an insulator was for a CD 138.9 Miller "twin pin". The only mint example of a CD 138.9 known brought over $30,000 when it sold several years ago. Hmmm... An amber CD 158.9 is also known to exist.. Would it bring even more than the emerald green?