Where gear cutting fits
The gear teeth should not be considered independently from the rest of the component. Bore, shaft, shoulder and datum geometry influence how the blank is held and how tooth position is controlled through manufacture.
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Gear types suited to cutting
Ondrives' published capability includes spur gears, helical gears, worms and wormwheels within the relevant machine and tooling ranges.
Spur gears
Straight teeth parallel to the shaft axis.
Helical gears
Angled teeth requiring helix angle and hand to be defined.
Worm-drive components
Worm and wormwheel geometry manufactured as part of the complete transmission requirement.
Drawing data that helps manufacture
Useful information includes module m (for helical gears usually normal module mn), tooth count z, pressure angle α, helix angle β and hand, profile shift x, face width b, material, heat treatment, quality grade and datum scheme.
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Use the engineering tools
GearCALC can help review basic geometry before a drawing is released. Final production data should always be checked against the drawing, mating gear and applicable standard.
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Need help with a specific gear?
Send Ondrives the drawing, model or available gear data. For new designs, include the operating duty and mating-component information so the manufacturing route can be reviewed in context.
Gear cutting geometry and process control
Tooth cutting is governed by the gear system and by how the blank is located. Small differences in module convention, pressure angle, helix convention, hand or datum relationship can make nominally similar gears incompatible.
Module and pressure angle
Module m defines tooth size. For helical gears, normal module mn is in the plane normal to the tooth trace while transverse module mt is in the plane perpendicular to the axis. Pressure angle must be stated in the same reference system and be compatible with the mate.
Helix angle β and hand
For helical gears identify helix angle β, left/right hand and whether module and pressure angle are normal or transverse. For a parallel-shaft external pair the mates normally have opposite hands and equal helix-angle magnitude. Hover axial pitch / lead for the associated axial relationship.
Blank and datum quality
Bore, faces, journals and locating diameters influence how accurately the teeth can be generated relative to the component. Concentricity, runout and workholding should be considered before cutting starts.
Hobbing is commonly suited to external cylindrical gearing; shaping can provide access to internal gears and features that restrict hob run-out. The actual process is selected from geometry, access, quality, material and quantity rather than the gear name alone.