toothing with re-entrant angle When a gear wheel is being manufactured, if the number of teeth is below the lower limit (e.g. 12 teeth), then the tooth faces must be made with a re- entrant angle. This process weakens the tooth faces. description ordernumber 370 see also: vane-pump spindle drive free from backlash Path-measuring system (made-up of two models) pilot operated directional control valve