In November, 1925, the Society of Automotive Engineers requested the American Standards Association
to take up the unification of the various systems employed in gaging wire and sheet metal in order
to arrive at an American standard system of designating diameters of metal wires and the
thicknesses of metal sheets.
The ASA called a conference on Wire and Sheet Metal Gages for March 18, 1926, to study the
diversity of gage systems. Representatives of government departments, trade associations,
manufacturers, and users participated in the conference which approved the initiation of this
project and appointed a special committee to frame the scope and to recommend the sponsors. This
special committee recommended that The American Society of Mechanical Engineers and the Society of
Automotive Engineers be appointed joint sponsors for the project, and that the scope of the work
cover the standardization of a method of designating the diameter of metal and metal alloy wire,
the thickness of metals and metal alloys in sheet, plate, and strip form, and the wall thickness of
tubing, piping, and casing made of these materials; and the establishment of a standard series, or
a number of standard series, of nominal sizes.
The Society of Automotive Engineers as administrative sponsor issued invitations to the cooperating
bodies and the organization meeting of the sectional committee was held on November 27, 1928.
The National Bureau of Standards as well as several large industrial organizations have prepared
and published data over a period of years in an effort to coordinate existing gaging practice.
Design engineers and fabricators of material had begun to use thousandths of an inch where
previously they expressed thickness in terms of gage numbers. Preferred numbers were suggested to
replace existing gage systems as a means of unifying the practice. The sheet and strip steel and
the steel wire industries had met the situation of unification by listing decimals of an inch in a
prominent way in their extra tables and by using them to set up lines of demarcation.
After a period of committee inactivity, the American Society of Mechanical Engineers took over the
administrative leadership in September, 1939, and a meeting of the sectional committee was held on
November 3, 1939. At that meeting the committee accepted the scope as defined by the previous
committee and elected a subcommittee to study this subject in detail and to prepare recommendations
for action by the sectional committee.
Several meetings of the subcommittee were held culminating in a report which was duplicated in May,
1940, for criticism and comment. A revised draft, dated January, 1941, was approved by the
sectional committee, the sponsors, and the ASA. It was approved as an American Standard in August,
1941, with the designation ASA B32.1-1941.
At a meeting of the sectional Committee on April 12, 1950, it was voted to modify the standard by
expanding the 20-series to the 40-series of preferred numbers, and to add an appendix containing
the 80-series for use in special cases. This was changed upon motion made at the October 25, 1951,
meeting of the sectional committee, and subsequent approval by letter ballot, The appendix covering
the 80-series was deleted from the proposal but reference to it was retained in the body of the
Approval of the sectional committee on the July, 1950, draft followed, together with that of the
sponsors and the ASA. Final designation as an American Standard was granted on September 30, 1952.
The proposed change in the title of the B32 project from "Wire and Sheet Metal Gages" to "Wire
Diameters and Metal Thicknesses" was also approved by the sectional committee, sponsors, and ASA.