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Gallery: 20 of 21

Guy wire strains are used to break the conductivity of a guy wire. They are placed in-line in the guy wire; the two ends of the wire are threaded through each other's eyes with the strain in between, held in compression, so that if the strain were to break, the guy wire would still hold, albeit without insulation.
JB 10 (No CD) L = 2 13/16" D = 1 15/16" U.S.			Very rare egg-style, only one known. This has been in a hobby for many years and is thought to be American, but there is no proof. As with all eggs, the two mold halves are clamped together and the glass poured through a port in the side; the glass is then broken off, and remaining stub is ground flush; hence overall dimensions do not vary.
JB 20 (No CD) L = 3 1/8" D = 2 3/16" U.S.			Another very rare egg, one of two known in this style (both straw). Also known in the hobby for many years, and thought to be American, perhaps a West Coast glass company-- the straw color is reminiscent of Maydwell.
JB 30 (CD 1130) L = 3" D = 2¼" U.S.			Smaller of the two California (C.G.I.) strains. This uncommon egg is embossed at one end, on the top lip "10" (the factory style number) above "CALIFORNIA", and on the bottom lip "PAT APL'D FOR". Like all eggs, it has a large round grind mark at the pouring port. Comes in sage green only.
JB 31 (CD 1131) L = 3½" D = 2¾" U.S.			Larger of the two California (C.G.I.) strains. Also embossed at one end, on the top lip "15" (the factory style number) above "CALIFORNIA", and on the bottom lip "PAT APL'D FOR". Both egg styles are about equally uncommon. Like all eggs, it has a large round grind mark at the pouring port. Comes in sage green (left), smoke, SCA and yellow.
JB 35 (No CD) L = 3 1/8" D = 2¼" France			With the nicest color of all strain insulators, meet the unembossed Folembray egg, in the characteristic factory color, a rich dark yellow-green-- se bon! There are dozens of these in the hobby, many introduced by Bernie Warren, who excavated them from a canal in xxx in yyy (see the Crown Jewels story, xxx yyy).
JB 38 (CD 1138) L = 2½" D = 2¼" U.S.			The classic small "johnny ball", most common of all guy wire strain insulators, made by Brookfield and Hemingray in large numbers. The two mold halves slide together, so depending on the amount of glass poured, the length varies anywhere from < 2¼" to > 2½". As there is no pouring port, there are no grind marks either. Colors: ice to dark aqua, milky light aqua. Ice and milky are rare, light aqua is uncommon, aqua and dark aqua are common.
JB 40 (CD 1140) L = 3¼" D = 2¾" U.S.			The larger size classic "johnny ball", less common than the smaller size, also made by Brookfield and Hemingray. Made the same way as the small one, with two mold halves which slide together, so length depends on the amount of glass poured and varies from < 3¼" to > 3½". No grind marks since no pouring port. Colors: light to dark aqua and green aqua. Light aqua and green aqua are uncommon; aqua and dark aqua are the regular colors.
JB 50 (No CD) L = 3" D = 3" U.S.			Very rare "baseball" style strain, only a couple known in the hobby. Pretty much a round 3" ball, but very crudely made so dimensions are nominal. Not sure how the mold works: there is no pouring port or grind marks, and the mold lines are as all egg insulators, with two halves meeting in the middle, doesn't seem meant to slip. It's got a serious underpour, but that doesn't seem to be where the glass was added. Hmm. Aqua only.
JB 60 (No CD) L = 4" D = 2¾" Germany			This German strain has an unusual asymmetrical design: each end is different. One end has the normal open groove, but the other end forms a closed eye. It's at the closed end that the pouring port is located, since the sides are concave and don't offer a likely spot. The pouring stub is broken off and ground, but just to remove sharp edges, not ground flush-- they don't seem to care if it sticks out quite a bit. Note measurements do not include stub. Comes in clear, light straw, and light aqua.