https://mechcalc.net/blog/en/tags/k%C3%BCbler-equation/ Recent content in Kübler Equation on MechCalc how-to Guide https://mechcalc.net/blog/og-default.png https://mechcalc.net/blog/og-default.png Hugo en Mon, 13 Apr 2026 18:00:00 +0200 https://mechcalc.net/blog/en/posts/bolt-preselection-02-reduction-factors/ Mon, 13 Apr 2026 18:00:00 +0200 https://mechcalc.net/blog/en/posts/bolt-preselection-02-reduction-factors/ Where does the reduction factor κ in bolt pre-selection come from? Starting from the two-way stress state where axial tensile stress and torsional shear stress combine during tightening, this article uses the von Mises yield criterion to derive the definition, formula and engineering values of κ, explaining how thread friction acts like an 'invisible tax' that cuts the bolt's axial load capacity, and why it appears in the denominator of the Kübler equation. https://mechcalc.net/blog/en/posts/bolt-preselection-01-load-to-size/ Thu, 26 Mar 2026 20:58:00 +0100 https://mechcalc.net/blog/en/posts/bolt-preselection-01-load-to-size/ For a given working load, how large should the bolt be? This article covers the preliminary design and pre-selection of bolts: first read the nominal diameter and property class from a quick pre-selection table by load range, then use the Kübler equation to back out the thread stress cross-section from the axial working load and the required clamping force, combined with the tightening factor, reduction factor and simplified fatigue and bearing-pressure checks, to help engineers quickly size a bolt in the early design stage.