CD 185-189

Pinhole goes all the way through

CD 186.1

CD 186.1

Size: 82mm x 98mm (3.25" x 3.875")




Years produced: 1940
Style (CD) scarcity: 2, Less then 10 known
Intended use: Spark Gap Insulator
Style / catalog number: 19
Number of unique insulators:
Notes: Experimental Spark Gap Insulator, based off a standard Hemingray 19 but with a modified top. Patented Jan 8, 1946, Patent No. 2,392,342. One of three prototype styles. In addition to the CD 186.1, there are the CD 186 and CD 186.2. All styles are rare, but the CD 186.2 seems to be the more available of the three.

Primary Embossing = Embossing on the front of the insulator, usually is that manufacturers name or the customers name. No embossing units will be noted as NO EMBOSSING. Units with no name but with numbers or letters will be noted as NO NAME.


EIN = Embossing Index Number is a standardized way to identify each unique embossing.

(FS) = Front Skirt
(RS) = Rear Skirt
(DO) = Dome
(CR) = Crown
(FC) = Front Crown
(RC) = Rear Crown
(BG) = Between Grooves
(FA ) = Front, Above wire groove
(FB) = Front, Below wire groove
(BE) = Base Embossed
(FU) = Front Umbrella
(RU) = Rear Umbrella
(FCE) = Front Center
(RCE) = Rear Center
(TE) = Top Ear
(TOP) = Top of Pinhole
/ = Next line of embossing

There are unique characteristics of the insulator that are not related to the embossing, but is worth noting.

Factory molded brass bushing
Flaired skirt
MLOB = Mold Line Over Base
Waffle top
Wide saddle groove

Base = the bottom of the insulator. It is noted in the following standardized ways.

SDP = Sharp Drip Points
RDP = Round Drip Points
CB = Corrugated Base
SB = Smooth Base

= Insulator has been verified that exists
= Insulator has been verified that exists, but not listed in the "guide"
= Insulator has not yet been verified as existing
= Suspected error listing in the "guide" because listing does not match up with known manufacturing practices. Such as numbers and dots on an aqua insulator, or insulators listed with both factory molded brass bushing and without. Many do not come in both configurations and are listed as coming in both. Etc.

Color = The approximate color of the insulator. Due to manufacturing variations, insulators with the same color name maybe slightly different in actual appearance.

Primary Embossing EIN Embossing Special Features Base Color Verified?



(FS) HEMINGRAY-19/(Numbers and dots) (RS) MADE IN U.S.A./(Number)



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