The original Z-Axis frame will break if you over force a bit the screws to clamp the z axis linear rails. This leads to loose rails and will result in a high frequency vibration of the whole spindle.
This is caused by a bad printing orientation of the original Z-Axis frame. It is too easy to break the layer adhesion.
The top and bottom parts of this replacement frame will be printed in a better orientation to be stronger against the forces of the z-axis linear rail clamp screws.
To assemble the frame you'll need 20x M3x18 countersunk screws and 20x M3 nut.
Designspark Mechanical Downloads:
Cnc router CNC2417