<div id="heading"><h2 class="berschrift2"><a name="mod_1547187634361_0001"></a><a name="text_mod_1547187634361_0001"></a><a name="_Toc227140503"></a>Preliminary remarks</h2></div><p class="dlModulbegrenzung0"> </p><p class="dlModulbegrenzung0"> </p><p class="dlModulbegrenzung0"> </p><p class="dlModulbegrenzung0"> </p><p class="dlModulbegrenzung0"> </p><p class="dlModulbegrenzung0"> </p><p class="dlModulbegrenzung0"> </p><ul class="hb-list hb-list--bullet hb-list--square"><li class="hb-list__item">In accordance with their thread size and strength class, screws must be tightened crosswise to the specified tightening torque [see »Screw tightening torques« chapter]. When tightening the screws, do so evenly to prevent any distortion under load.</li><li class="hb-list__item">To avoid precision errors, clean all screw-fitting points and mating surfaces [Notes on cleaning, see »Cleaning« chapter]. Factory wetting of flat surfaces and, where necessary of clamping elements, only serves as a corrosion inhibitor. This is not functionally related lubrication.</li><li class="hb-list__item">Only apply lubricant to the mechanical mating surfaces. Pay attention to notes about lubricants [see »Use of lubricants« chapter].</li><li class="hb-list__item"><span class="numbering-span">•</span>Avoid too much lubricant on the locating face because this can cause face run-out errors.</li><li class="hb-list__item">Apply grease to the sealing elements [for example O-rings, rectangular rings] and sealing surfaces. Pay attention to notes about greases [see »Use of lubricants« chapter].</li><li class="hb-list__item">Do not damage the functional surfaces [flat, mating, tapered and sealing surfaces].</li></ul>