Abstract: A roller assembly primarily adapted for sanitary uses includes an amorphous thermoplastic roller tube and crystalline thermoplastic end caps. Each end cap includes a tapered hub and a radial flange. A plurality of tapered barbs are formed on the hub. The end caps and tube are mechanically interconnected by an ultrasonic insertion device which causes melting and resolidifying of the roller tube about the end cap. The roller tube is held and the end cap is guided to a concentric position by a clamp havig a pair of jaws which define a bore. The tube is clamped in the bore during insertion of the end cap.