Another blank panel.
But this time I'll clamp it properly!
Distributing the force over the entire short side.
Now that I can't get to the edge, this is my improvise edge finding method.
After getting everything clamped so well it turned out I can't get the collet chuck close enough to the edge to make the features. So plan B takes shape...
Supports for the edges.
Supports for the edges that actually fit.
Finally, making the large slot.
And the small ones. The not-quite-through slot is due to the collet chuck hitting the clamps in the Z direction this time.
Close enough for testing.