Few people noticed when the United States Metric Board disappeared from federal organizational charts last week, and fewer people mourned. In fact, it says something about the agency's short and quirky life that the loudest laments came from a man who prefers inches and gallons to meters and liters.

"The fact that we existed and kept federal agencies aware of people's feelings made them move more cautiously" when they approached metric conversion, said Thomas Hannigan, an executive of the International Brotherhood of Electrical Workers and a labor representative on the Metric Board. "Now," he sighed, "they're going to be able to do whatever they want to do."

Back when a metric-conversion agency was first discussed in the early 1970s, the scientists and international businesses who backed conversion seemed to dominate the discussion. But by the time the U.S. board actually appeared in 1978, the tone of the discussion had changed drastically. Small businesses and large labor unions crying "go slow" had become the dominant political voices.

So the board itself was left with a murky mandate: to educate the public, to glean information on which industries are converting and what problems they face, to help coordinate federal agencies' use of the metric system, but to avoid advocating metrics over the conventional system of measurements.

That mandate has now passed to the Office of Voluntary Metric Conversion, a Commerce Department unit staffed by four professionals, all that is left of the board's 35 employes.

John Tascher will still be keeping tabs on federal agencies' activities -- whether procurement contracts will be written with metric or conventional specifications, what kind of measurements agencies use in their publications, and so on. Linda Cook will still be filling requests for information and encouraging private efforts to educate the public about metrics. Alan Whelihan will be keeping in touch with states and the National Council on State Metrication. And a new office director will eventually replace Ed McEvoy.

"The board's staff did feel it had a mission," Cook said. "We worked hard to inform people and to set up coordinating mechanisms so we could be sure that conversion, when it did occur, occurred smoothly and at a minimal cost. Being in Commerce now we have access to a bunch of information much more easily . . . "

The move from Rosslyn to 14th Street and Constitution Avenues NW, from the status of an independent agency to one small office in a big bureaucracy, has been relatively painless, Cook said.

The biggest change, she said, will be the office's narrowed mission and reduced budget. The board in its last year had $2 million to spend; the new office has about $300,000. "We were ranging far and wide to educate people, which wasn't easy because we couldn't advocate. Now we have to look to other people to do most of that."

Chief among the "other people" is the American National Metric Council, a Bethesda-based spinoff of the American National Standards Institute. The Metric Council, which has ties to a wide range of industry groups, is headed by a supporter of metric conversion.

The demise of the Metric Board, said ANMC president David Gorin, "puts us in a much more important role. We are the focal point much more than we were" for coordination on metric conversion. ". . . The middle ground in this issue is the only sane one: does it make sense for a particular industry? This issue is going to be played out in industries with an international perspective."