Double Groove Pony
by Greg Kareofelas
Reprinted from "INSULATORS - Crown Jewels of the Wire", March 1970, page 7

As I stated previously this series of articles will investigate a particular style of insulators in detail. In this article we will take a look at the double groove pony.

Almost all the major companies producing insulators offered at least one variety of double groove pony. The two major styles of double grooves are simply the two major styles of pony insulators with the addition of the lower groove.

This is the earlier style of pony insulator having a second groove.

This is the later style of pony with an additional groove.

The double groove pony is an example of a special purpose insulator. Because the need for this type of insulator was relatively small, there was never a large number made and most are scarce today.  The extra groove provided an insulated anchor point for a service connection.

Most of the phone men of this period, however, were not schooled in technicalities and usually anchored this line either to the pin or the crossarm not using this insulator. So, very few double grooves were probably ever used for the purpose they were actually designed for. Most still seen on lines today are mixed in with, and function as a single groove pony.

Because this insulator had two grooves, some rural phone men used it as a transposition insulator. It was not too effective or easy to use in this manner, because it has such shallow wire grooves.

The following known companies, and styles they produced are listed as follows. The drawings are somewhat stylized and not to scale. The numbers in parenthesis are our CK Numbers.

CD 112:     Brookfield (5-BR-01), Lynchburg (5-LY-01), OVG (5-OV-01), California (5-CA-01), Hawley (5-HA-01),      SF (5-SF-01), Sterling (5-SR-01), S.B.T & T. Co. (5-SB-01), Hemingray (5.3-HM-01), Star (5-ST-01) & (5.2-ST-01).
CD 112: Brookfield(5.1-BR-01), B (5.1-BB-01)
CD 113: Armstrong (8-AR-01), Whitall Tatum (8-WT-01), Hemingray (8-HM-01 to 8-HM-03), Star (8-ST-01)
CD 114: Hemingray (6.5-HM-01).