Changing between Mertic and imperial the easy way - Episode 245

These are unusual times we are living in. Trapped at home with only a long list of jobs that I have been avoiding for years.
I received a question the other day about running files in imperial on a metric machine and it seemed like a good topic to cover as it is not the first time i have been asked this. When you first set up your machine you need to choose the unit of measurement that you want to use on your machine. If you live in the USA you will most likely choose imperial and if you live anywhere else you will probably choose metric. Having made the decision are you stuck with your choice or can you change it easily? Fortunately Gcode has some commands built in just for this situation. G20 & G21
While Control software like Mach3, Mach4, LinuxCNC & Masso  use G20 &G21 other software like UCCNC do not. But all is not lost. If you want to use he other unit of measure you just need to make a 2nd profile. 1 for Metric and the other for imperial. Not as good as using G20, G21 but it still works.

So the long and the short of it is that no matter what Native unit of measurement you set up in your machine you can machine any Gcode file given to you in any unit of measure. 

Is it advisable? That is a completely different question. While I am not keen to run other peoples Gcode on my machine and any Gcode I make will always be metric I can see where this could be very handy. In these times of makers spaces where a CNC machine is a communal item it is likely that some people will want to work in Metric while others work in imperial. This is where the G20, G21 will shine. Users can design what they want in whatever unit of measure they want and can still machine it on the same machine. 

So next time someone gives you a Gcode file that is in the wrong unit of measure, you will know that you are able run it anyway.

In the meantime I hope you all keep safe, keep washing your hands and try not to touch your face. 

Cheers 
Peter