G98 and G99 Codes Introduction
G98 and G99 codes are use with drilling cycles like G81, G83, G84 and etc.. for CNC Milling machines (CNC Machine Centre)
G98 and G99 Codes Format
When specifying G98 code, the tool coming from the bottom of a hole, returns to the initial
When specifying G99, the tool returns to the R level from the bottom of a hole.
Things to Know
The figure below describes the movement of the tool when G98 or G99 is specified.
G99 is generally applied for the first drilling operation, while G98 is applied for
the last drilling operation. Even when drilling is performed in the G99 mode, the
initial level does not change.