The main goal of gear cutting tools is to achieve high productivity, while eliminating wasted motion and maintaining a high gear quality. Although Scudding® is quite recent, today it is possible to state that scudding® tools meet all of the above benefits.

Scudding® is defined as a continuous cutting operation that uses a tool design similar to a helical shaper cutter. A great advantage of this technology is it can be applied to many gear applications including involute gears, non-involute gears or non-symmetrical gears.

The process is extremely flexible, reduces cycle times and completely eliminates unproductive upstrokes due to the synchronization of the cutting tool and workpiece. Another advantage in using this technology is that you can perform the machining of internal or external gears without the need of an undercut or groove.

Scudding® can cut a gear in equal cycle time as hobbing and can be five to six times faster than shaping an internal gear due to skiving’s continuous chip removal capability. It can also be used to hard-finish gears with a carbide cutter and can be applied any time a form can be generated by shaping, hobbing or broaching.

This process is becoming very efficient due to the latest machine technology (direct drive and stiff electronic gearboxes) and tool technology (complex geometry, material and coating).

So, scudding ® does not have any wasted strokes and compared to broaching, can use the machine axes to make lead corrections such as crown and taper.

Cutting speed calculation

Cutting speed is obtained by a combination of workpiece rotation speed, tool rotation speed and the intersection angle between them. It is generated by the cross axis angle between tool and workpiece.

Inclination angle:       Σ = b0 ± b2

Cutting speed:                  vc = vTool · sinb0 + vWorkpiece · sin b2

  • For Spur Gear the axial feed fa is directed in line with the Y axis.
  • For helical gear the axial feed fa is oriented in y-direction but an incremental tool rotation nTool has to be added to tool rotation nTool.
  • A tilt angle can be used to increase the effective relief angles.



  • Produce predetermined flank corrections
  • Taper and crown can be set via machine parameters
  • Improve the rolling action of the gear
  • High productivity
  • High gear quality with low surface roughness
  • Reduce cycle times
  • Dry cutting
  • Hardened work pieces can be machined