An effective CNC program respects considerations such as ease of use and program-to-program consistency that go beyond just driving the machine in a particular application.
While G65 does not enable users to simply and easily carry out Custom Macros in multiple locations, G66 and G66.1 provide modal solutions for doing so.
While CNC machining and turning systems of the past only had resolutions and least input increments equal to the displayed decimal places, new systems support more precise inputs.
While it is possible to calculate by hand adjustments to feed rate for circular milling operations, cutter radius compensation CNC programs streamline this process.
Maintaining a constant feed rate between linear and circular milling easily leads to chatter — for most applications, increase feed rate on external arcs and decrease it for internal.