THE SCHOOL BOARD'S threat to furlough 8,800 employees this September to avoid a $4.8 million deficit seems a political ploy as much as a sign of fiscal desperation. The board has known since last September, if not since before then, that it was on track to run a deficit. The size of that prospective deficit went down as the board made some program cut and changes.

But now the board -- with two months left in the fiscal year -- is asking the mayor to make up a $4.8 million school system deficit or hear the public outcry that will come when schools delay buying supplies and repairing schools and take $500 out of every teacher's paycheck.

The mayor's position has been that the board must handle its money shortage like every other city agency. He and his aides have long argued that there is waste in the school systems's budget and that the board should deal with that waste before it involves the plight of children to attract public sympathy and money to keep board members from making budget reductions. Despite his opinion, the mayor has increased the school budget for next year from his original allotment (but not as much as the board wanted), and he has helped the board to get about $1 million in a budget supplement for this year. The school board is still not satisfied and says that the money is not nearly enough.

Conceivably, the mayor could do more for the school budget. He has been slow to compromise with the board on how much the schools need for next year, and he has not done all that much to help with this year's shortfall. The mayor, however, is not responsible for making the school budget work. The school board has that job. And the school board has defaulted by allowing the circumstances to reach a point where apprently only furloughs of employees could balance the accounts. Teachers should not have to sacrifice $500 to compensate for the school board's negligence.

Although people talk of certain ways in which Mayor Barry could come to the rescue, the burden in this sad episode rests with the school board. There are measures other than the furlough method it can use to eliminate the deficit. After all, the $4.8 million is only a tiny percentage of the total school budget; responsible administrators should be able to handle so relatively small a problem without resorting to drastic steps, even if they have only two months left in the fiscal year to do it.