radius compensation right

G42 is the G-code for radius compensation right. Radius compensation allows the programer to program for the features of the part without regard to cutter diameter. Without radius compensation the programer would have to calculate how far to offset the tool in order to machine the part and would have to do this for every diametter of tool used. With radius compensation the programer can simply call for the radius of the tool from controller memory address and tell it to offset the tool path to compensate.

Example

N100 G42 H3 (offset for the radius of the tool in H3)
N... XY ... (cutting part)
N... XY.... (cutting part)
N... XY.... (cutting part)
N200 G40 (cancel the tool offset and continue)

In the above example the controller is asked to recalculate the tool path based on the cutter radius which is stored in the controller at the H3 memory address location (location 3 is used as example only as it could be any number allowed by the controller).

With G42 the part shown above could be machined as is with any cutter diameter. See also radius compensation and radius compensation left