[Garciabyron218]

Recently got a 4x8 CNC router and I'm new to all this.

Here's my scenario.

Let's say I have a 4"tall x 12"wide piece of wood that I want to engrave a name right in the center.
I know how to set up the CAD/CAM and then export the gcode to mach3.
I'll find the zero on the corner and set up the machine but how do I make sure my piece is square?

Ideal set up would be like pic1 and the word is centered in the piece. But what if I find the zero but the piece is skewed ever so slightly, the words wont be squares like pic2. How do I tell the machine how exactly the piece is oriented so even if the piece is skewed, then the words are too like pic 3

What tool/software/add ons do I need to do this or is it just measuring from the edges of the machine and try to set the piece as best as I can

Any help is appreciated

[ger21]

How do I tell the machine how exactly the piece is oriented so even if the piece is skewed, then the words are too like pic 3

You'd need to probe the edge to find the angle, and use G68 to rotate the machines coordinate system.

It's much easier to just measure.
Or engrave some lines in the spoilboard to line up the board to.

[firepong]

If your spoilboard has any type of hold down (drilled and tapped holes, T-Nuts, etc), you can use dowel pins. On mine, I have 1/4 drilled and tapped holes. I'll stick a 1/4 dowel in the holes for the aide of the work piece and the bottom, giving me a square surface on 2 sides of the machine. Then I will put a side pressure hold down on the 2 sides that are opposite the dowels, giving me good hold on all 4 sides. Just look up mitee-bite and you will see what I mean about the side clamps.

Depending on the thickness and type of material I use will decide what type of dowel pins I use. I will chuck the wooden ones up in my drill press and sand them all down to the same thickness, with different lengths for different thicknesses. I also have some aluminum round bar at different lengths, but I had to get those hit on a lathe to get them 100% round all the way around. If you don't have a lathe, you should be able to find some precision turned round stock somewhere with a tolerance of +-.005, which should work just fine.