Apparatus for clamping two drums to an upright support, the drums each having a projecting bracket or brackets, defining at least one through opening, comprising a carrier body connectable to the upright support, posts on the carrier body receivable in bracket openings, and adjustable mechanism on the carrier body for displacing at least one of the posts relative to at least one bracket opening to clamp at least two posts against the brackets. Certain posts may be carried by structure connected to the drums; and certain post receiving openings may be carried by the upright support.