Estimate contact and tooth-root stress for an external spur or helical gear pair from geometry, torque and explicit ISO 6336 factors.
Use this for early selection of module, facewidth and allowable material stresses. Factors remain visible so their source in charts, tables or material data is traceable.
Enter torque, geometry and factors.
Pre-size tooth-root and flank capacity with transparent geometry and load factors.
Module, tooth counts, face width, torque, pressure angle and material/load factors Z, Y and K.
Factors Z, Y and K are not arbitrary safety values: they represent geometry, load distribution, quality and material effects. A blanket choice can materially over- or underestimate capacity.
ISO 6336 separates tooth-root stress and flank pressure. Geometry and load factors combine with nominal forces; safety compares stress with allowable value.
Increasing face width lowers specific tooth force approximately inversely at unchanged torque.
Sources and limits: ISO 6336-1/-2/-3/-5/-6; select factors from geometry, quality, load spectrum and material data.
Pre-size tooth-root and flank capacity with transparent geometry and load factors.
Mechanical calculators translate geometry and load into a response such as torque, stress, deflection, spring force or bearing life. The position of the load relative to the effective axis is often decisive.
ISO 6336 separates tooth-root stress and flank pressure. Geometry and load factors combine with nominal forces; safety compares stress with allowable value.
Module, tooth counts, face width, torque, pressure angle and material/load factors Z, Y and K. Factors Z, Y and K are not arbitrary safety values: they represent geometry, load distribution, quality and material effects. A blanket choice can materially over- or underestimate capacity.
Enter module, tooth counts, face width, torque and pressure angle, plus the applicable geometry, material and load factors (Z, Y and K values). The calculator compares resulting tooth-root and flank stress with the allowable material stress.
Increasing face width lowers specific tooth force approximately inversely at unchanged torque.
Factors Z, Y and K are not arbitrary safety values: they represent geometry, load distribution, quality and material effects. A blanket choice can materially over- or underestimate capacity. The result shows the idealized component response for the selected load case. A small change in diameter, height, length or load can have a large effect because of power laws.
Module and width in millimetres, torque in N·m, stresses in MPa, factors dimensionless.
An initial capacity estimate for a gear pair in the concept phase, or checking how much a changed face width or increased torque affects safety against tooth-root or flank damage.
ISO 6336-1/-2/-3/-5/-6; select factors from geometry, quality, load spectrum and material data.
Common mistake: Don't set factors Z, Y and K to 1 by default or carry them over from a different project – they depend on gear quality, load spectrum, operating temperature and lubrication, and can strongly change the result. Tooth-root and flank capacity are two separate checks; passing one does not substitute for the other.
Tooth-root capacity concerns tooth breakage at its root from bending stress; flank capacity concerns pitting on the tooth surface from Hertzian contact pressure – both require separate checks.
ISO 6336-2/-3 provides charts and formulas depending on gear quality, tooth count and operating conditions; generic assumptions without a source are not sufficient for a real design.
It shows the chosen model meets the standard. Manufacturing quality, real load spectra, heat treatment and operational lubrication additionally determine whether this calculated safety is actually achieved.
All main influencing quantities are shown as inputs or intermediate results. Check factors, material data and boundary conditions against the complete standard.
The local standards provide terminology and series values. This tool deliberately identifies its simplified scope and does not claim conformity.
Use the result as a starting point for selection and plausibility; then verify manufacturer data, load spectra and safety requirements.