ST-6750-6874

254mm - 298mm (10" - 11.75")
ST-6755
ST-6755
ST-6755
Size: 255mm (10”)
Example in Photo: J-D (USA)
Photo Credit: Mid Norris
Direct link to this insulator:
ManufacturerInsulator MarkingsCap MarkingsColorCountry
JD(Under-glaze Ink) (JD Logo) MFG. (Date)P / 550BrownUSA
ST-6800
ST-6800
ST-6800
Size: 282mm (11.125")
Example in Photo: No Name (J-D) (USA)
Photo Credit: Mid Norris
Patent: 1,329,770 - Patented Feb. 3,1920
Patent: 1,716,963 - Patented June 11, 1929
Direct link to this insulator:
ManufacturerInsulator MarkingsCap MarkingsColorCountry
JD(Under-glaze Ink) (JD Logo) / Date / NumbersLight BlueUSA
JD(Under-glaze Ink) (JD Logo) / MFG. (date) / Pat. Nos. 1,329,770 & 1,716,963Light BlueUSA
JD(Under-glaze Ink) HI MFG. J-D (Date) / Pat. Nos. 1,329,770 & 1,716,963Light BlueUSA
JD(Under-glaze Ink) MFG. J-D (Date) / Pat. Nos. 1,329,770 & 1,716,963Light BlueUSA
JD(Under-glaze Ink) Numbers / (JD Logo) / MFG. (date) / Pat. Nos. 1,329,770 & 1,716,963Light BlueUSA
No Name (J-D)BrownUSA
No Name (J-D)Light BlueUSA
No Name (J-D)(Under-glaze Ink) MFG - (Month) - (Year) / (Number)BrownUSA
No Name (J-D)(Under-glaze Ink) Pat. Feb 3, 1920 Mfg. (Date)BrownUSA
No Name (J-D)(Under-glaze Ink) Pat. Feb 3, 1920 Mfg. (Date)Light BlueUSA
ST-6800A
ST-6800A
ST-6800A
Size: 282mm (11.125")
Example in Photo: J-D (USA)
Photo Credit: Mid Norris
Patent: 1,329,770 - Patented Feb. 3,1920
Patent: 1,716,963 - Patented June 11, 1929
Note: interesting story on the ST-6800A, It is marked JD but was made by Pittsburg high-voltage, and has a Pittsburg date stamp on the top. The story goes that JD had a large order for the standard ST-6800s but could not make them fast enough to fill the orader so had Pittsburgh help!
Direct link to this insulator:
ManufacturerInsulator MarkingsCap MarkingsColorCountry
JD(Incuse) (Date)Light BlueUSA
JD(Incuse) (Date)J.D.CO./DETROIT // PAT. PDG.Light BlueUSA
ST-6805
ST-6805
ST-6805
Size: 279mm (11")
Example in Photo: No Name (J-D) (USA)
Photo Credit: Mid Norris
Patent: 1,329,770 - Patented Feb. 3,1920
Direct link to this insulator:
ManufacturerInsulator MarkingsCap MarkingsColorCountry
No Name (J-D)(Under-glaze Ink) Mfg. Nov. 1930/HITLight BlueUSA
ST-6825
ST-6825
ST-6825
Size: 285mm (11.25”)
Example in Photo: No Name (J-D) (USA)
Photo Credit: Shaun Kotlarsky
In the collection of: Curtis Erickson

NOTE: Typically we would not assign a number to a disc with out the hardware, The only exception is experimental discs that never had hardware like this example from the J-D Dump.
Direct link to this insulator:
ManufacturerInsulator MarkingsCap MarkingsColorCountry
No Name (J-D)Light BlueUSA