Print 2 of each .stl part.  

Needs 4 bearing assemblies. (https://www.amazon.com/dp/B082PQ3SC4?psc=1&ref=ppx_yo2_dt_b_product_details) 8mm id : 16mm od : 5mm width.

Designed in Free Cad.  (I'm still learning.)  Free Cad files are included if you want to modify. 

Glue the two tabs that hold this thing together.  Much more stable.

I'm new to all this and learning. I welcome suggestions of any sort.  Thanks.