This model works great for printing filament directly from dry boxes and is adjustable for larger filament spools (print the longer dovetail slide model for 1kg+ spools). Use superglue to lock in M / F frames after inserting bearings and add a few drops on the "legs" of the model to make sure the frames stay parallel. After assembling the frame, bearings, and legs, insert the dovetail slide to force alignment and adjust distance for your filament size. 

608 2RS Bearings that I used: https://www.amazon.com/dp/B09PKD8QZZ?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1 

3D Printer Glue I used: Amazon.com: 3D Printer Super Glue Thin for PLA, ABS, PETG, TPU & Nylon – 1.76 oz XXL – Capillary Action, Ultra Fast-Drying & Clear – Perfect for Resin, RC Parts, Cracks & Fine Detail Fixes : Industrial & Scientific