Beaten gold, not hollow, but solid and massive gold, beaten out of one piece, and not of several pieces joined or soldered together. See Exodus 25:18,31 Exodus 37:17.
Related Commentaries of Numbers 8:4
Numbers 8:4
4 And this work of the candlestick was of beaten gold, unto the shaft thereof, unto the flowers thereof, was beaten work: according unto the pattern which the LORD had shewed Moses, so he made the candlestick.