Abstract: A reuse method for utilising reject rolls being produced in paper and cardboard factories, wherein from the reject rolls (1) there are made straight roll cores (8) having the same size in their inner and external diameter and varying in length, the straight roll cores being defined by the width of each reject roll (2); the straight roll cores are joined end-to-end to form a long, continuous core tube (12), and the core tube is cut to size to form roll cores (14) of paper and cardboard industry.

Abstract: A reuse method for utilising reject rolls being produced in paper and cardboard factories, wherein from the reject rolls (1) there are made straight roll cores (8) having the same size in their inner and external diameter and varying in length, the straight roll cores being defined by the width of each reject roll (2); the straight roll cores are joined end-to-end to form a long, continuous core tube (12), and the core tube is cut to size to form roll cores (14) of paper and cardboard industry.

Abstract: An abutment joint for end-to-end joining of paper reel cores, the abutment joint comprising a first conical surface (4) formed on the outer surface of one core (2) and a second conical surface (3) formed on the inner surface of the other core (1), whereby said first conical surface and said second conical surface abut against each other in the joint, wherein at least one protrusion (6) is formed at least on one conical surface and at least one groove (5) is formed at least on the other conical surface to form an interlocking joint between the cores.