A Collector's Guide
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Lynchburg Base Types
All early insulators had a smooth base rim. Toward the end of the 19th century, drip points (DPs) came into use on the base of insulators. Drip points were a series of glass extensions around the base of the insulator, most commonly cone shaped (usually called sharp drip points, SDP). The idea was to help water shed off the insulator more quickly thus reducing the risk of a short circuit between the wire and the pin. Drip points were originally patented May 2, 1893, by R. G. Hemingray and J. C. Gill, and the patent was assigned to the Hemingray Glass Company. However, by the time Lynchburg started production in November of 1923, the patent had expired and the technique was available to Lynchburg.
There were different ways to make drip points. The easiest and most common was a separate single "collar" around the base of the two lower insulator mold halves (after the late 1880s molds were three pieces with the crown or top third a separate piece). This collar had indentations machined into it that formed the raised drip points when the glass was forced into the mold. Since insulators were pressed with the crown down and the base facing up, this collar would be on the top during the manufacturing process. This accounts for instances of incompletely formed drip points due to air bubbles in the glass being forced to the top in the process of pressing glass into the mold.
In most instances, the collar containing the drip point mold could be interchanged with a smooth base collar without changing the actual insulator mold. This allowed the same insulator mold to occur with both smooth base and drip points. It also allowed different numbers and types of drip points on the same insulator style since various collars could be used on the same mold.
There may be instances of an originally smooth base mold being modified directly into drip points without the use of a collar, but by the 1920s this would be unusual. In a few cases the DP collar was not machined accurately or was done hurriedly and the drip points are of uneven spacing and height.
Most of the early Lynchburg insulators had fairly evenly formed and spaced CDP. The company later used RDP on CDs 106, 112, 122, 154, 160, 162, 164, 306. We are not sure of the reason for the switch, but was likely due to the tendency of CDP to chip easily (see Birmingham).
In its brochures, Lynchburg Glass Corporation advertised its insulators with drip points unless the customer specified a smooth base. As a result, most Lynchburg insulators are found with drip points. All styles of Lynchburg insulators occur with drip points, but not all styles occur with smooth base. And not all mold numbers of styles that occur with both drip points and smooth base are found with smooth base. Of the fourteen styles of Lynchburgs, only five occur with a smooth base: CDs 122 (rare), 162, 164, 205, and 251 (rare-unconfirmed).
Most collectors only identify three varieties of bases: sharp (or cone) drip points (SDP or CDP), round drip points (RDP), and smooth base (SB). The list below includes other varieties of bases as well as minor variations found on Lynchburg insulators.
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Copyright © April 5, 2018 , Dennis Bratcher
Last modified: September 28, 2015 7:54 AM