A dowel for establishing a sliding attachment between two plates (2, 3) provided with slot holes (4, 5) arranged one against the other with their respective slot holes (4, 5) perpendicular to and facing one another forming a passage for said dowel, wherein it is formed by a first part and a second part which is detachably pressure-coupled to said first part, characterized in that: - said first part comprises a first head and two first pins (7a, 8a) extending in cantilever fashion from said first head, said two first pins (7a, 8a) facing and being separated from one another by a space, and wherein at least one of said first pins (7a, 8a) is able to experience an elastic bending that moves them away from one another; first retaining projections arranged in a first axial plane being formed at the free ends of said first pins (7a, 8a); and said first head being provided with a through hole that leads into said space separating said first pins (7a, 8a); - said second part comprises a second head and two second pins (7b, 8b) extending in cantilever fashion from said second head, said two second pins (7b, 8b) facing and being separated from one another, and wherein at least one of said second pins (7b, 8b) is able to experience an elastic bending that moves them closer to one another; said second pins (7b, 8b) being shaped such that they pass through the through hole of the first part and are introduced under pressure into said space between the two first pins (7a, 8a), thereby causing an elastic bending of at least one of said first pins (7a, 8a) that moves them away from one another to a final coupling position in which the head of the second part rests against the head of the first part; and there being formed at the free ends of said second pins (7b, 8b) second retaining projections which in said final coupling position are arranged in a second axial plane perpendicular to said first axial plane and project with respect to said first pins (7a, 8a) laterally in said second axial plane; - said first part and said second part are shaped such that in said final coupling position they fit with one another preventing the rotation of said second part with respect to said first part. - said first part comprises a first head and two first pins (7a, 8a) extending in cantilever fashion from said first head, said two first pins (7a, 8a) facing and being separated from one another by a space, and wherein at least one of said first pins (7a, 8a) is able to experience an elastic bending that moves them away from one another; first retaining projections arranged in a first axial plane being formed at the free ends of said first pins (7a, 8a); and said first head being provided with a through hole that leads into said space separating said first pins (7a, 8a); - said second part comprises a second head and two second pins (7b, 8b) extending in cantilever fashion from said second head, said two second pins (7b, 8b) facing and being separated from one another, and wherein at least one of said second pins (7b, 8b) is able to experience an elastic bending that moves them closer to one another; said second pins (7b, 8b) being shaped such that they pass through the through hole of the first part and are introduced under pressure into said space between the two first pins (7a, 8a), thereby causing an elastic bending of at least one of said first pins (7a, 8a) that moves them away from one another to a final coupling position in which the head of the second part rests against the head of the first part; and there being formed at the free ends of said second pins (7b, 8b) second retaining projections which in said final coupling position are arranged in a second axial plane perpendicular to said first axial plane and project with respect to said first pins (7a, 8a) laterally in said second axial plane; - said first part and said second part are shaped such that in said final coupling position they fit with one another preventing the rotation of said second part with respect to said first part.