Refer to the following Community Garden post regarding this topic.
Be warned that you need to use a strong adhesive to connect the bushing or it will fail. I used 2P-10 (a type of wood super glue) and it failed after about a week). I had to break it down and redo it. The second time I used a $2 two part epoxy from Harbor Freight. This seems to be holding well.
Note: 2P-10 is amazing for holding wood parts together when assembling. It is not cheap, but holds wood great and sets in seconds.
I think that there is so much about the z that is cool and yet so much to improve on. What if the whole locking mechanism was rethought through someone’s 3d print. something that stops the pivot (popping out of spindle recess) but easily disabled (changing bits) keeps it on track with the ridge that is there (take out slop), and the third was going to try and cover the button that has already been printed but what if it were completely different? just my thoughts that keep occurring. Seems like so many little problems in that very small place in the universe.