1/4-20 Knob with Nut Trap

I made this clamp knob using the customizer and http://www.thingiverse.com/thing:713300. I wanted the 1/4-20 nut to be trapped inside, so I modified the knob to do that.

Print with the larger surface down. The last layer of the nut trap is at 9mm, so edit your g-code by searching for G1 Z9 - it should find a line like G1 Z9.000 (this could be different, depending on your layer heights. I printed with .3 layer height, so Z9.000 was exact for me). On the line before this one, enter @pause. The