EFIS v5 - Printing Shafts

I am having problems with the Range/Function switch shafts. Everything seems to fit together nicely and functions. I run into problems when the shafts protrude from the faceplate and I attach the knobs. I think the grub screws when tight enough to keep the knob from rotating on the shaft causes stresses in the shaft and they snap off. I have tried to be gentle...I have purchased and downloaded the v5 package.