Drive for rolling mill calibration unit Adjustment of calibration roller as a worm gearbox Not only the slab thickness must be maintained on the rolled steel slabs, but also the width and length of the slabs. During the rolling process the slabs are pressed by a calibrating instrument that works on both sides. The worm gearbox manufactured by Kachelmann has a multiple-spline profile in the worm gear fixture. This enables the calibration spindle to be set at one dimension and at the same time retract over the spline profile. In this manner different dimensions can be calibrated.