Robot (1) to move a support platform (6) along a series of nuts (2) pre-screwed on bolts (3) arranged in a linear or in particular curved flange connection (4). The bolts (3) project from the nuts (2) pre-screwed in substantially a nut plane (13) by a projection length (15). The robot (1) comprises a drive to move the robot (1) along the curved flange connection (4). The drive comprises at least one drive element (12) and holding means (11) both connected to the support platform (6), wherein the holding means (11) comprise at least one pair of guiding rails (16, 17) connected to the support platform (6) in a distance from each other of more than the diameter (D) of the bolts (3) and less than the width across flat (AF) of the nuts (2) and projecting more than the projection length (15) from the support platform (6).