Pianist George Shearing has in abundance both the tools of his craft and the knowledge of the idiom, but he sometimes seeks too low a common denominator in performance. The nearly full house last night at Charlie's Georgetown indicated he retains a loyal, even avid, following and, if he wants to serve his many admirers well, he will edit out the flab and add some muscle to his act. He would do well to replace his tuneless vocals and the parodies of PDQ Bach with the kind of swinging piano he is quite capable of playing.

The opening set did have some high points, however. One of them was a two-piano romp by Shearing and his bassist Don Thompson. There were no hesitations as the four hands strode in step, circled minuet-like or traded phrases with abandon. Yet this was the solitary number on which the bassist utilized the second piano on the bandstand.

"One For Amos" was vintage Shearing with arpeggios gone wild and melodic comping beneath bassist Thompson's own very melodic solos. Thompson, by the way, is not a grandstanding bassist but one with a sure feel for melody and a firm handle on rhythm. His high technique, coupled with subtlety of expression on one of the instruments' classic vehicles, Oscar Pettiford's "Tricotism," puts him in the first rank of today's bassists. Shearing's musical wit was well revealed in this piece in his many quote-filled exchanges with Thompson. The duo remains through Sunday.