RATRIG V-core4 Z constraint

This is an upgraded z constraint for the rat rig v-core 4 with some top surface details to increase strength and I added a support for the over hangs.

also there were some dimensional adjustments made as well to help engage the z screw a little better,  

I recommend splitting them into object and ironing the top pf the support structure. 

The clearance for it is very tight so take care when slicing

i sliced mine with a .6mm nozzle, 3 walls and 20% infill

these were made off the ratrig official cad release but was unable to add the url for it as a remix.