G20 not changing tools, is it normal?

My machine is setup in the INI file with mm, but if i program a G code with G20 my tools are still kept in mm.

From the documentation

unpy.net/emc2-docs-new/gcode_tool_compensation.html

The units used for the length and diameter of the tool may be in either millimeters or inches, but if the data is used by an NC program, the user must be sure the units used for a tool in the file are the same as the units in effect when NC code that uses the tool data is interpreted.

So according to this i should change my tools in inches before starting a G code in G20, but if I do my tools will be very very small, it appears that they are still in mm, i use G42-G41 a lot so tool diameters are very important, practically this is fine because i would not have to change my tools to work with G20 because they are fine they way i always use them in mm, but I'd prefer it to be like the way it is written in the documentation, is there a special g-code to do this?

If not please fix the documentation, because it does not reflect what the interpreter actually does right now...

i'm using latest 2.5 stable version

Hi

This is the official 2.5 docs address
linuxcnc.org/docs/2.5/html/gcode/tool_compensation.html

You will see it is considerably different to the one you linked to, which seems to be from Jeff Eplers website.

It simply states that tool offsets are in machine units.

From this I would expect that should anyone want to work in imperial units on a metric machine, that they would have a separate config and tool table for that, rather than just use G20 in G Code.

I quite often use imperial cutters with my milling machine, because there are a lot of them around still, especially in the bigger sizes. But I just use the metric equivalent for diameter.
As quite a few of them have been re-ground at some time, I actually measure them rather than assume that 1" will be 25.4mm etc.

regards