Have you ever wondered how a World War II hammer C46008 became hammer 5546008 in the late 1950s? This article will discuss drawing and part numbers and excludes entirely the revisions as nothing here will apply to revisions. In short, the information provided here pertains to the basic number only, which is referred to by ordnance publications as the part and/or drawing number. For ease I will use the term "part number," as, usually, the part number and drawing number are the same, unless reference is made to an entire assembly (but that's another article for another time). To understand the system as it came to be (i.e. hammer 5546008 or bolt 6528287), one must know about the World War II system and its evolution.
The World War II system was around since
the late 1920s and was known as the Standard Nomenclature System or SNL. The SNL
system, for today's researcher, is simple and pretty clear. A referenced part
under the SNL system consists of a prefix and a basic number. The letter "C" was
the prefix and "46008" was the basic number of the part. Ideally this basic
number is unique and signifies only the hammer for the Ml rifle.
The SNL system also provides a code to
identify parts that were packed for storage or issue. The format varied, but
somewhere on the package would be the code B021 or B21. B021- C46008 would allow
somebody to grab a printed SNL and find that B021 meant Ml rifle and C46008
meant hammer. Every major item within Ordnance Department
responsibility—including vehicles and tanks--had its own code.
As the war continued it became apparent
that items developed during the 1930's and earlier had four or five digit part
numbers, but items being developed by early war had six and seven digits
numbers. By mid-war groundwork was being laid for future uniformity by assigning
everything a seven digit part number.
In an effort to standardize all part
numbers to a seven digit system, the following formula was adopted:
prefix* Drop Letter and Add
to Basic Number**
This formula breaks down when a part
number contains a letter within its basic number. For example, D35410A became
7133230 in a random assignment. (This is an assumption made by this writer as
after many attempts I am still unable to establish a pattern.) You can use the
above formula to convert wartime part numbers to later ones (pre-1954 and
post-1954 will be covered in Part II). For those members who have access to ORD
December 1950, you will find the formula on page 3.
The seven digit system is found in certain
late-war SNLs, mostly for later developed items, but the heavy push for adoption
occurred during the post-war period. As of January 1, 1954 the seven digit
system was mandatory for immediate adoption into the Federal Stock Number
system, which encompassed everything within the federal supply system, not just
ordnance items. The Federal Stock Number system (FSN) is evident in the
Technical Manuals of the 1960s and lasted until 1972 when it was modified to the
National Stock Number System (NSN). The FSN system of the 1960s will be covered
in Part Two. Having an understanding of these systems will make researching
technical manuals more rewarding.
letters signify Drawing Size with "A" being the smallest and "E" being the
largest. Although not applied during the war for small arms, the "E" size shows
up in larger items.
**Dropping prefixes was supposed to occur, but 1950s production had lots of Cs, Ds, and Fs.
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