An assembly having a first piece and a hollow second piece, the first piece having upper and lower parts which are connected by a hinge-forming part and form a space, a part of the second piece being accommodated in the space, the hollow second piece includes a cavity and a bushing is provided in at least part of the cavity, the bushing being provided at a level of a part of the hollow second piece that is accommodated in the first piece. The assembly further has a clamping unit that brings together the upper and lower parts of the first piece. The assembly relates in particular to the manufacture of tools for cutting, shearing, clamping or gripping, such as pruning shears. The assembly also concerns an assembly kit and a method for achieving an assembly.