An arrangement for transforming a planar support (2) includes first and second rotating cylindrical transformation tools (16, 17), cooperating to convert the support (2), first and second side bearings (26, 27), holding the first tool (16) for rotation (Rs), third and fourth side bearings (29, 31), holding the second tool (17) for rotation (Ri), spacers (43, 44, 46, 47) having an inclined face (48) and slidable (S) to adjust the respective distances (e, e1, e2) between the first and third bearings (26, 29) and between the second and fourth bearings (27, 31), to set a radial gap (20) between the two tools (16, 17). In another solution, either as an alternative to or in cooperation with the first solution, the spacer (43) is moved (S) by a differential screw (57) having a first thread (58) that engages with a tapped hole (59) in an integral part (61) of one of the bearings (29) and a second thread (62) different than the first thread (58) and engaging with a tapped hole (63) in the spacer (43).