All those people who wondered whatever happened to ''Cap the Knife'' know now: On one issue at least - military spare parts - he's swung into action at the Pentagon. It's an action other government executives ought to emulate.
During his previous tenure as secretary of the old Department of Health, Education and Welfare, Caspar W. Weinberger earned his nickname for cost-slashing propensities. When he became Secretary of Defense in the Reagan administration many expected similar parsimony; to the outside world that has not happened - until now.
Shortly before he left on a three-day tour of Central America, Secretary Weinberger ordered major improvements within three months in the way the Pentagon buys spare parts - an area greatly in need of revision. Aim of the changes is to see that the government obtains parts at lowest possible prices, whether they are as mundane as bolts or as sophisticated as electronic gear.
Earlier this year several reports charged the military with paying ridiculously high prices with taxpayer money for various items - as extreme as $ 17.59 for a 67-cent bolt. One of the most important changes needed was for the military to have more than one supplier for each item: the new Weinberger order insists that this be done.
Other federal agencies also have internal problems that need similar tough-minded attention from the top. Anyone who has dealt at length with federal agencies knows that many departments, despite having some splendid employees, are riddled with inefficient procedures and rules; these waste the time and sap the morale of government employees and civilians alike. Too often the requirements of federal programs ironically prevent them from succeeding.
Administrators in other department agencies should take action akin to that of ''Cap the Knife'': identify organizational problems that waste time and money , move vigorously to outline solutions and demand that these promptly be instituted. It is neither necessary nor wise to take on the most massive problems first: modest successes breed an atmosphere in which complex situations more easily can be dealt with.
Two ingredients are essential. One is recognition from the top down that inefficiencies and wasteful administrative procedures need not be tolerated under the guise of ''business as usual.'' The other is the courage to take necessary corrective action.