CDs 287, 287.1, and 287.2

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The Insulators

Left to Right, Top to Bottom:

Row 1:
  • CD 287.2 BROOKFIELD [020], Wide dome variant, Aqua
  • CD 287.2 LOCKE [010], Gray
  • CD 287.2 LOCKE [010], Gray
  • CD 287.2 BROOKFEILD [010], Narrow dome variant, Light Aqua

Row 4:

  • CD 287.1 LOCKE [010], Light Aqua, Smallest Extension
  • CD 287.1 LOCKE [010], Light Aqua, Large Extension
  • CD 287.1 LOCKE [010], Light Aqua, Larger Extension
  • CD 287.1 LOCKE [010], Light Aqua, Largest Extension
Row 2:
  • CD 287.1 LOCKE [010], Red Amber, No Extension
  • CD 287.1 LOCKE [010], Peacock Blue, No Extension
  • CD 287.1 LOCKE [010], Depression Green (7-up Green per the PG), No Extension

Row 5:

  • CD 287.1 LOCKE [010], Light Aqua, No Extension
  • CD 287.1 LOCKE [010], Peacock Blue, No Extension
  • CD 287.1 LOCKE [010], Aqua, No Extension
Row 3:
  • CD 204 LOCKE [010], Blue Aqua
  • CD 204 LOCKE [010], Light Aqua

Copy at the bottom of display is a copy of an advertisement from the March 4, 1893 Electrical World, showing a CD 287.2, and advertising the Fred M. Locke & Co. steel pin with cast iron base.

Some Additional Facts

  • The CD 287.1 LOCKE [010] pieces in Red Amber, Peacock Blue, and 7-up Green are known to have been manufactured by Hemingray.
  • All CD 287.1s, as well as the CD 204s, carry the May 22, 1894 patent date
  • The "F. M. LOCKE & CO." was a partnership that lasted from November 14, 1892 to May 13, 1895. The "& CO" was dropped from embossings after the partnership ended.
  • A March 4, 1893 ad (as shown at the bottom of the display) depicts the CD 287.2
  • A March 10, 1894 ad depicts the CD 287.
  • There is one CD 287.1 listed in the price guide that has a blotted out "& CO".
  • There is one CD 287 listed in the price guide [070] that has a "& CO" in the embossing, not blotted out
  • Many CD 287s are listed in the price guide with blot outs of "& CO" or "F.M. LOCKE & CO".
  • The Brookfield CD 287.2s do not have a patent date listed, but say "PATENTS PENDING"
  • The Locke CD 287.2s have the May 22, 1894 patent date, but do not say "& CO" (nor is there room in the embossing for a blot out of "& CO").

Study Observations

  • The CD 204 insulators were mold mates, i.e. made in the same mold
  • The CD 287.2 LOCKE insulators were mold mates.
  • There were several mold mates among the CD 287.1s. Some colored specimens matched molds with some of the aqua specimens. * Some colored specimens matched molds with other colored specimens. Some aqua specimens matched other aqua specimens with different skirt extension lengths.
  • Embossing style matched between the CD 287.2 LOCKEs, the CD 204s, and all the CD 287.1s. A number of insulators known to have been made by Hemingray were also brought, and the embossing styles were compared. Hemingray embossing was consistently fine and angular, especially as observed in the "&". Brookfield embossing was noticeably coarser and rounder. The CD 287.2 LOCKE, CD 204, and CD 287.1 embossings were consistent with the known Hemingray specimens.
  • There were 5 different observed skirt lengths for the CD 287.1s. This ranged from no extension on all of the colored and some of the aqua specimens, to 4 extension lengths on the aqua insulators. Extensions were observed on the light aqua pieces only -- the darker aqua pieces did not have extensions.

Additonal Observations

  • Paul Greaves reports that ALL CD 287s have MLOB (both RB and SB) and appear to be Brookfield made. Note that a [070] specimen has not been observed and thus may be different.
  • Bill Meier reports that the CD 287.1 listed in the price guide with a blotted out "& CO" may be in error. His records indicate he had reported this insulator, but that upon closer examination it is probably an unlisted CD 287 embossing.
  • According to N.R. Woodward, all CD 287.1 have the skirts "all level", and not extended. CD 287 was intended to have an extended skirt, but due to underpours some are not.


  • All "& CO" embossed units were manufactured by Hemingray, including all CD 204s, and all CD 287.1s.
  • The CD 287.2 LOCKE was made by Hemingray.

Still Up For Debate

The Timeline Originally, it was thought that the CD 287.2 was introduced by Fred Locke around 1893. The narrow dome variant was probably first, then the wide dome variant with slightly extended middle skirt was an improvement. The CD 287.1 was introduced some time after May 22, 1894, and continued in production until around the time of the dissolution of the partnership in mid-1895. The CD 287 was then produced for a number of years. However, there are a few problems with that theory:

  • The CD 287.2 LOCKE does not bear "& CO" in the embossing, and does include the May 22, 1894 patent date. It was obviously made after mid-1894, and probably after mid-1895 when the partnership ended. That could mean that it was made after production of the CD 287.1s had ceased.
  • Ads for the CD 287.1 appear well before the patent date in 1894. This would appear to be early enough to overlap the supposed introduction of the CD 287.2.
  • Many of the presumably Brookfield made CD 287s have a blot out of "& CO". Were these molds made by Brookfield (which would contradict our theory that all "& CO" insulators are Hemingray), or could they have been Hemingray molds converted by Brookfield (in which case, why change the embossing style while blotting out the "& CO"?)

Alternate Timeline CD 287.1 was introduced, manufactured by Hemingray, sometime around mid 1894. About a year later, Locke had Hemingray make the CD 287.2. At about the same time or a little thereafter, Locke switched to Brookfield, and they made the narrow dome variant of CD 287.2. A little thereafter, they made the wide dome variant. Brookfield obtained the CD 287.1 molds originally used by Hemingray, reworked them into the CD 287 (causing some blotouts to remain visible), and subsequently continued to make this shape. There's a couple problems with this theory, too:

  • A March 4, 1893 ad depicts the CD 287.2
  • If Brookfield made the CD 287.2 after May 22, 1894, why didn't they emboss this patent date on the insulator?

Alternate Timeline 2: Perhaps the Brookfield CD287.2s were the first production of this general style. That would explain the "Patents Pending" embossing. Later, Hemingray competed for the contract, and made some sample CD287.2s (or possibly a prototype run). Locke desired that they beef them up a little (perhaps due to customer feedback) and they created the CD287.1. This process could have been happening in the 2nd half of 1894, and the lack of "& CO" embossing on the CD287.2 was an oversight that was corrected for the final product. (Fred Locke had a bit of an ego it seems, so I can easily imagine him ordering the F.M.Locke embossing, and the partners balking and asking for the "& CO." to be added. It is also possible that one of Fred's partners had a connection to Hemingray, and that is why they changed vendors.) The improved version (CD287.1) went into production before the partnership dissolved in 1895. The CD287.1 could have been made for a while after the partnership dissolved, if the molds were not re-embossed right away.

Later, sometime after the partnership had dissolved, Locke switched back to Brookfield. I strongly suspect that the molds were transferred to Brookfield, and re-worked. In that process, the diameter was increased slightly, the embossing re-engraved to strengthen it, and the "& CO" blotted out. The base was also modified to give it the "MLOB" characteristic, and the inner skirt configuration was changed slightly so they are typically extended with the inner most skirt recessed. So far, all examples I have seen have the additional mold seam around the outside of the base, indicating a likely mold modification.

Even later, as the molds wore out, Brookfield made new molds, and these have no evidence of the "& CO." embossing, or the additional mold seam around the outside of the base. Brookfield continued to make this style for many years, explaining the examples with just the style number and no "Locke" embossing at all.

The correct answer is probably none of these, but some combination of them, with perhaps some overlap in production dates.

Continuing Research

If you have a CD 287 LOCKE [070] (which has the "F.M.LOCKE & CO" marking, not blotted out), we would love to see it. Also, if you have a CD 287.1 LOCKE [020] (which has the "& CO" blotted out), we'd like to see that too. Both of these pieces could give meaningful clues as to the topics discussed here.

Many Thanks

to those who contributed insulators for examination, and who discussed the questions surrounding these insulators:

  • Andrew Gibson
  • Elton Gish
  • Paul Greaves
  • Bill Meier
  • Bob Stahr
  • Ron Yuhas
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