Triangle M

Triangle M, like Macomb, is not a manufactuer, but  the second marking produced by Illinois Electrical Porcelain Co. "Macomb" being the oldest. Originally  Illinois used underglazed blue ink stamped triangle M marking (according to Tod this marking was introduced in 1915 when Illinois began manufacturing wet processed insulators). Incised triangle M markings followed and the two styles of stamps were used until circa 1926 when the Illinoias state/date/model marking began.

U 256A's Click on the last (darkest) 256A to see a negative photo that reveals a nearly impossible to see marking

Six U 263's

Want to tackle an interesting little insulator mystery?  No one knows what the 5 incised "dots" are for, 2 on the left of the triangle and three on the right.  To date I have only seen these dots present on Tri M's that are incised. One clue may or not be that this marking was used from appx. 1916 to around 1926. Tod even called these a "manufacturing date code . . ." however, there never seems to be any variation in the number of dots per insulator nor any change in the positioning on the mark (compare to the Lapp date code lines).  Certainly needs solving.

U 300's

U 316A's

The following are all unmarked signals that can be attributted to TriangleM (Illinois) production click here to read more

U 263

U 265A

U 266's

U 268's

U# ??? a deformed U 266, or maybe a deformed U 265A (TriM is not credited with making a U 265A)

A deformed U 268?

Characteristics: Color(s) --- wood tone red brown, dark brown, reddish brown, brown with cream highlights, butterscotch, sky blue, white, brown, mottled dark brown and cream, two tone dark brown top butterscotch bottom, reddish brown with blue highlights, blue Pinhole(s) --- glazed with the exception of the butterscotch U 263 Pinhole Top(s) --- wide variety of pinhole tops, from slight dome to various sized indentations. Fire Rested --- U 300's and the U 316A's are petticoat rested, all the rest are skirt rested Wet/Dry Processed --- wet Marking(s) --- U 256A's are blue ink stamped on dome "M" inside trianlgle with no dots. U 263's are either ink stamped with  the same mark or are incised the same. U 300's are marked "M" in a triangle with 2 dots on upper left of triangle and 3 dots on upper right of triangle and the model number "237" underneath the triangle. U 316A's are the same marking as U 300 except model number is "234"