#349 Coil Perfs

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Rather than learning coil identification by rote, start with the business problem. The Bureau was faced with production bottlenecks, quality issues and increasing demand for stamps. . Changes in watermark, perforations and ultimately the development of the rotary press all related to the need to print larger quantities of better stamps at a lower cost. Coils were developed in response to a desire to support high speed affixing machines and stamp vending machines. Initially coils had to be cut up from sheets of stamps perforated in one direction. Imperforate coils were also made available. Because stamp collectors did not take coils seriously until the changeover to perf 8 1/2, few were saved.

Substantial quantities of coils with fake perforations were sold to dealers (and collectors) even before World War II. Until Kiusalas produced the US Specialty Gauge in the late 1960s, fake perforations were generally not exactly the same gauge as genuine perforations. If imperforate coils were not available, like for the 4 and 5 cent horizontal coils, edges had to be cut by hand and were rarely parallel enough to be credible. As production processes changed, the characteristics of the coil edges changed. (The Micarelli Guide lists stamps that can be altered to resemble a coil or scarce perforation variety.) With very limited exceptions, genuine coil edges must be parallel. When comparing edges, the same stamp should be compared top to bottom. (When comparing perforations, a different stamp should be used.)