Fifth Bureau Definitive
The Presidential Series
1938 - 1954

by Lt Col John P McGowan
USAF Reserve, Retired

It was the purpose of this study to: (1) illustrate changes in sheet margins made from newly designed plates for implementation of new technologic processes, (2) acquaint and assist viewers in understanding these changes by seeing and comparing pre-eye and electric eye margin marks.

One of the great succcesses of the Bureau engineers, aided by the General Electric Company, was the development of the perforator machines which automatically controlled sheet alignment prior to perforation.

This method of perforating sheets by means of perforators controlled by photoelectric cells was a definite change in stamp manufacturing and should be of real interest to the student of 20th century stamps. Stamps that show various marginal markings is a specialized accumulation.

The viewer is assisted by seeing marginal guide line marks which appear in the gutters from the original type pre-eye plates and comparing them to bars and dashes of the electric eye plates.

The older stationary perforating machine used a manually adjusted sheet carriage. In spite of the operator's keen eye and alert switch control, adjustments were so far off center that sheet stock had to be destroyed after perforation. Loss was very heavy for this reason.

Speedier production resulted from automated control of electric eye perforators. The quality of holes, from pins and wheels punched on printed and pre-gummed reels of sheets, improved tremendously. Waste was reduced by half.

Moveable perforators operated entirely by the Bemrose principle but were limited to use on web carriages. Several electric eyes scanned gutter dashes and frame bars which started relays for perforation. Guide markings on plates remained the same for all experiments. The web passed through gum breaker rollers which kept the gummed paper from curling and helped maintain proper tension.

Additional adjustments were made as the web, constantly weaving, moved onward toward the next group of two electric eyes. When the web carriage was misaligned, photoelectric cells automatically activated relays to make proper adjustments for realignment. Markings were engraved on pre-eye prexy plates. Markings were 'rocked-in' on EE plates. Scott recognizes the validity of collecting marginal marks, especially prexy experimental marks.

Electric eyes scanned the outer longitudinal margins of the web. The outer bar, margin line, and frame bars activated relays which controlled the machine's centering for latitudinal perforators. Pins and wheels rotated in the same direction and fully punched a line of holes across the web as it passed. This second longitudinal perforator's last action trimmed and cut the web into sheets. The travel direction of the paper never changed.

The philatelist will study various types of prexy marginal markings, along with numbers and corners that identify plates. This extremely important issue spanned a period of major conversion in production of United States postage stamps.

The prexy collecting domain encompasses mostly inexpensive stamps. Serious collectors might be hard-pressed to locate postally used varieties, more so than unused materials. Several desireable stamps are so few they will never be included in most collections.

Any Scott catalogue will read, 'Although many exist used, and are scarce in that condition, ... they are less sought after.'

Postage stamps are printed and sold for a prepaid service. When they have been purchased, affixed, posted, canceled, carried, and delivered, service has been performed. Then postage stamps have done the job for which they were intended.

source:

George C Hahn, The American Philatelist, Vol 55 #2, Nov 41, pp86-95.
Miers and Rustad, United States Specialist, Vol 51 #11, pp545-549 thru Vol 55 #12, pp575-576.
John M Hotchner, United States Specialist, Errors, ... Aug 1982, pp370-373. Six letters, 1992.
Max Johl, United States Postage Stamps of the 20th Century, Vol 3, pp245-250.
George W Brett, American Philatelic Congress Yearbook for 1958, pp76-100. Five letters, 1990.
HebertÕs Standard Plate Number Single Catalogue, 1986, pp1-A221.

Revision Dated: 11-19-2001