crazy mirror problem

I have often dealt with issues of mirroring, sometimes intentional, sometimes accidental but this one is new..

the school where I teach has a cnc router with a table that measures approx 24 by 24...


one of my students has a 3d profile for a part of our school play... the piece is approximately 27 inches long..

to make the billet "somewhat fit" we rotated the part around the z axis, (so that it JUST fits on the table) at about a 45 degree angle..

and to simplify the process I instructed the student to make his 0,0 at the center of the part... (as indicated by the star at the center of the drawing below)

<img src="https://docs.google.com/drawings/d/1TQ2VKg0L0KslLnW5MbaIfXVtz1l_IuOXuOOl3Ro4hCs/pub?w=960&amp;h=720">


anyhow.. now we want to mirror the entire part..

if this were a typical situation (and if the part were aligned with the x axis,) we would simply set my x, or y axis to -1 in the mach 3 controller,


but because the "billet" is at a 45 degree angle to both x and y (on the table), I am thinking he will need to make both x, and y axis's -1.. to "flip" the entire part to create a mirror image..

I think this will also put the billet in the same "place" on the table.. (ie we can fixture our material in the same physical place on the table)

anyone want to offer an opinion? I will be sharing your contributions with my student / class.. thanks..

Personally, I would just mirror it in my CAD/CAM program. Doesn't mirroring with Mach3's scale reverse the toolpath direction? This would not be desirable for me in most cases.
If you want to mirror it in Mach3, I believe that you would only set the scale to -1in one axis only. If you set the scale for both the X and Y axis, I think that you would just be rotating the part 180°. Don't have Mach3 here to check, though.