sc8uu carriage spacer for raising carriage

.scad file so you can change the spacer size, its just the height of the first cube.

3 models for 1cm and .5cm spacings, just for the sc8uu on top, because the default printer were making my wing nuts - thumbwheels hit the reprap frame.

i think it's ok, 24mm spacing on x, 18mm on y, should be fine. screw holes are 5mm and expecting 4mm bolts.