Up Improved extruder top.

One leg broke off my up extruder top and the crack was hidden behind the motor. It started playing up as the stepper cog could push itself away from the wire and stop printing intermittently. But the leg didn't fall off completely because the crack was next to a screw which kept it held together...
It had also cracked where the heater wire pass out the side. I discovered the cracks and redrew the part with larger radii in the corners and stronger legs.
Now version 5 even stronger and thicker where it broke so I have counter bored the cap screw heads.