Abstract: A bending and forming device is disclosed having an operating head and its holder features a holder which is a multi part structure including a saddle for seating the head and a releasably connected gib, a limited portion of which is adapted to releasably bear on and hold the head to and for a rocking or rotative movement thereof on its seat. The head is preferably a cylindrical body having a groove the length of its outer peripheral surface, the bounding walls of which groove determine the operation to which the head may be applied. The retention device is connected to the saddle so as to enable an easy adjustment of its position to accommodate variation in the dimension of the operating head or wear of the related parts. In preferred embodiments the saddle affords a concentrated load bearing surface for the head provided by relatively narrow, adjacent and relatively spaced, longitudinally extended, strip-like bearings.