1 begins by controller input of table configuration depending on the type of aircraft stringer 93 fig3 which is to be fabricated into the computerized controller not shown the table configuration includes such parameters as the length of the stringer 93 and the variations in thickness along the length of the stringer 93 for example in fig1 the flopper assemblies 44 are operated to extend the pairs of mandrel cradles 51 through the respective module slots 16 fig1 in the table module 2 of the structure assembly table 1 in fig1 a left hand mandrel 88 and a right hand mandrel 88 a each of which receives a pair of respective c shaped stringer charges 89 is placed on the mandrel cradles 51 of the flopper assemblies 44 the left hand mandrel 88 and right hand mandrel 88 a extend in generally parallel relationship with respect to the longitudinal axis of the table module 2 and each other in fig1 and 13 the mandrel cradles 51 of the respective flopper assemblies 44 are rotated outwardly to turn the left hand mandrel 88 and right hand mandrel 88 a and respective stringer charges 89 away from each other in a horizontal orientation as shown in fig1 the flopper assemblies 44 are shown with the mandrels 88 88 a and stringer charges 89 in the raised position in fig5 in fig1 the mandrel cradles 51 are lowered.