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Looking forward to trying that out.

This will be the plan:
1.  Start Mach3
2.  G40 and G49
3.  Jog router to a safe spot with Z raised a couple inches
4.  Click Ref All Home in Machine Coordinates
5.  Jog router to stock/part and zero X Y Z
6.  Make sure G28 is "no" from Fusion
7.  Let it rip

Yes, when setting G28 to no then Fusion uses G54.  What I was still confused about was in Mach3...Under config...Fixtures - there's a screen where you can fill in values for G54 and save them.  But if my understanding is correct then I should just leave that area alone (don't save a G54)...And when I start a new part the work zero becomes the G54 for that particular project.

Also, when I close Mach3 I have been saying no if it asks if I want to save fixture changes.

Haha, there are always "those guys".  I definitely appreciate all the tips and help...I've been at this for about a week total so still LOTS to learn.  I've peeked at the Mach3 manual and get in over my head pretty quick but it really is a pretty amazing piece of software, never worked with anything that is so configurable.

I had to reread but yup...You said meters!  I get nervous when my little toy "rapids" more than a few inches haha.  I was already talking to the wife about building a bigger machine...Even a 1 meter footprint would be quite a bit larger.

Anyway, back on topic, I will try the G40 G49....Most likely, as in I'm 99% sure any "error" is all on me.

That's a good tip about G54 just going straight home...I'm going to look back at a couple of my earlier attempts and see what the ending code was.  The cutter definitely returned to the part zero at the end but not sure if by way of G28 or 54.

Lots to learn, definitely having fun though.

Thanks again

Looks like you guys replied as I was typing...Definitely not thinking about editing the Fusion post process (talk about being a dangerous haha)...Just wondered if there was a quick and dirty trick almost like a failsafe for a monkey like me to avoid dragging the cutter through anymore parts

Dixedanc and Dude1...thank you for the help!

Dixedanc - "you will want machine coordinate Z-0 at the top of your Z travel, and then use the Z offset to bring the cutter down to the correct position for cutting your program.", to accomplish that would I start the machine and open up Mach3...jog the machine to say the lower left corner and raise the Z and then hit "REF ALL HOME" to zero the machine coordinates (because I don't have switches, the 'poor man's version', no automation)...then jog the machine over to position on the stock and zero out XYZ (not the machine coordinates - just 'normal'? XYZ - not sure what the term is for XYZ coordinates that aren't the machine coordinates...but understand that there is a significant difference  :))

I've tried the above in simulation (leaving the code exactly as is from Fusion - with the G28 in play) and it looks like I'd drag the cutter.  Still in simulation...if I do all of the above but then raise the cutter manually up after zeroing it on top of the part but NOT re-zeroing with the new + value before starting the run...then it appears that it moves to where it wants to start, cycles the Z and then drops in.  So the 'work around' in that case is just don't forget to manually raise the Z...

Dude1 - looking at your advice, if I understand correctly - in Fusion 360 I should set "useG28" to "No" - doing that the new code produced by Fusion looks similar to what you typed out.  

New question...doing that do I now need to actually set some numbers in the Work Offsets config / G54 fixture line?

And second new question...I don't have a vice or anything and just stick the stock down to the table wherever looks good...is G54 'absolute'? (meaning from 'job to job' when I re-zero the cutter on the stock the G54 will reference the most current zero, not whatever zero was when I saved the G54 fixture?)

I haven't tried that yet...and may answer my own question.  I don't have my head fully wrapped around G54 either...but thinking based on my "sticking the stock wherever looks good" method I probably don't want to have a G54 saved in Mach3...but will essentially manually set the G54 for the 'job' when I zero out the router on the stock.  And if I just remember to add a line with something like "G0 Z0.5" before everything else the cutter will rise up and not drag over the stock if I forget to manually raise it before starting the program.

Third new question...is there a way to get Fusion to automatically always just insert the "lift the Z before doing anything else" command? :) 

Thank you again for taking the time to reply!

Hi Rich,

Thank you for this post!  Brand new to using a CNC / Fusion / G-Code / Mach3...and loving it!

Everything was working great except for the fact that on every program (G Code created with Fusion 360 Generic Mach3 post process) the machine would move to the starting point without raising the bit off Z zero...resulting in a nice straight groove across the face of the stock...or, if I manually raised the Z a little and started the program from there then it wouldn't cut all the way through the stock.  Also, at the end of the program it would only raise to the Z zero height and then return to X zero and Y zero resulting in another nice straight groove across the face of the finished part.  GAAAAAH

My machine is a simple 3-axis router DIY setup WITHOUT limit/home switches and I haven't learned enough yet to use soft limits, work offsets, etc. etc.  Like you said, trying to start as simple as possible.

Taking your advice I changed the start of the program from this:
(T1  D=0.25 CR=0. - ZMIN=-0.67 - FLAT END MILL)
G90 G94 G91.1 G40 G49 G17
G28 G91 Z0.

T1 M6
S10000 M3
G0 X2.0088 Y2.8883
G43 Z0.65 H1
G1 Z-0.125 F10.
X2.016 Y2.9256 F20.
etc. etc. etc.

To this instead:
G0 Z0.25
G0 X2.0088 Y2.8883
G1 Z-0.125 F10.
X2.016 Y2.9256 F20.
etc. etc. etc.

If I have my head wrapped around this:
G20 is important because that defines programming in inches (the units the part is designed with)
G90 is absolute reference and important for simple simple
I don't fully understand what the Z0.25 was in the original code but I 'moved' it up and put G0 in there to raise the Z first and foremost
Then it moves to starting point, Z drops in and off it goes.  ;D

The other key part was at the end...the original Fusion code has:
G28 G91 Z0.
G28 X0. Y0.

And I just deleted all of it...granted the machine just 'stops' at the end of program and doesn't return to home or anything but that prevents any grooves getting cut in the finished part.

Is there a G code (G30?) with maybe G0 Z1.0 to raise the bit up and then move the router back to the home starting point?

Anyway, long post but thank you again!

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