Bolted Joints & Torque
Every bolted joints & torque calculator on CalcEngines — each with its formula, a worked example, the standard it follows and the assumptions it makes.
7 calculators in this section
- Bolt Fatigue Under Alternating Load CalculatorThe alternating stress a preloaded bolt actually sees — Φ times the external load range, not the range itself — against VDI 2230's endurance amplitude and Shigley's endurance strength through Goodman, with the counter-intuitive result shown rather than asserted: raising preload usually improves fatigue life, because it stops the joint separating.
- Bolt Group Shear CalculatorA rectangular bolt group carrying an in-plane load with an eccentricity, by the elastic method — direct shear shared equally plus a torsional component from the centroid, with the resultant on the worst bolt — and the plate's bearing and tear-out capacity checked beside the bolt's, because that is usually the real limit.
- Bolt Proof Load and Tensile Stress Area CalculatorThe tensile stress area computed from ISO 898-1's own definition — the circle on the mean of the pitch and minor diameters, which is where the 0.938194 comes from — and the proof, yield, ultimate, clamp and shear loads that follow, for the metric property classes, for SAE grades with their size bands, and for the stainless classes that have no proof load at all.
- Bolt Torque CalculatorT = K·F·d, with the nut factor computed from friction rather than looked up, the torque split into the three terms it is made of — about half into friction under the head, two fifths into the thread, a tenth into stretching the bolt — and the preload band the chosen tightening method actually delivers printed beside the single torque figure. Every published nut factor this batch could source is tabulated and attributed.
- Bolted Joint Stiffness and Separation CalculatorBolt stiffness with the shank and thread in series, member stiffness from the Rotscher cone at a half-angle you can change, the load factor Φ they give — typically 0.15 to 0.25 for a steel joint, so the bolt feels a fifth of an external load — and the external load at which the joint separates and stops protecting it.
- Preload Accuracy by Tightening Method CalculatorWhat each tightening method actually guarantees from the same bolt. VDI 2230's tightening factors turned into a guaranteed minimum clamp load, the capacity the scatter wastes, the preload embedding costs computed from the joint's own stiffness, and how much more clamp load a better method buys — with four published scatter tables side by side and none of them averaged.
- Thread Engagement Length CalculatorHow deep the tapped hole has to be so that the bolt breaks before the thread strips — derived from the shear areas rather than quoted as 1.5 diameters, with the strength of the tapped material as an input, both published criteria evaluated and the larger governing, and an explanation of where the rule of thumb comes from and where it fails.