Here is a slight update to the Fusion 360 Post file. V5 just adds an initial Z raise of +10 so that it does not drag across the stock surface and so that it clears any hold down clamps that might be in the way. (Of course I have never ever milled though one of my printed holddown clamps 🙂 )
I realized that this post inserts “G92 X0 Y0 Z0″ at the beginning. This is nice because it sets the current tool location as the origin 0,0,0. Previously, before I knew about G92, I was cycling the power of my Arduino to reset the origin. In Fusion 360 CAM just select the milling origin at a convenient point on the stock box like the lower left corner surface top. Use the LCD or host or manually jog the tool tip to that location and start the job. It will automatically set that as the origin.
I did my first milling with a tool change midway and this post which maintains stepper lock worked great. I started with an 1/8″ end mill for surfacing and roughing, then changed to an 1/8″ ball mill for finishing. I have enclosed a screenshot of the Fusion 360 CAM screen and a mid milling photo of the test. It is a completely arbitrary object with some facing and a hand drawn squiggle with a cylinder cutout. It was milled on a length of 2×3” scrap. One helpful hint is to use a small block of wood with a slot cut in the side as a spacer to make sure all the milling bits are inserted to the same length. I included a photo of it below.
If others are using this post file please comment.