Simple easy-to-use space-saving MMU2 hanging spool system

Update 9/7/19: I fixed the M6 version of ACB. I had wrong thread pitch. I don't have much room on my small desk for MMU2 set up. And while I found the filament wallet reliable, it's painful to manually change filaments. I looked at other systems and they are often complex and can fail / wear out. The printed hangers can break, as I learned, or add too much friction for my liking. There are some very nice, very clever systems out there, to be sure. But I like simple and easy to use. I know this will not appeal to everyone. Note that this system is two solutions: simple cheap spool hangers for getting spools off your desk to save space, and very simple filament feed / retraction management (ACB) for MMU. They are separable. You can use one and not the other and combine with other solutions. **What I like:** super easy to slide new filament spool onto hanger; holds all sizes 1kg and smaller super easy to manually insert new filament to MMU by just shoving into ACB funnel. super easy to manually remove filament by holding ACB and turning spool to wind up ACB uses simple and reliable return spring: gravity (hasn't failed me yet) and doesn't tangle fun to watch ACB rising and falling **Parts needed:** 1x straight 1 1/8" wood [utility handle](https://www.amazon.com/Sandle-wood-handle/dp/B07QFSX7HS) (I found at Home Depot as TrueTemper 2700100) 5x [Everbilt rafter hanger](https://www.homedepot.com/p/Everbilt-8-in-Vinyl-Coated-Screw-In-Heavy-Duty-Steel-Rafter-Hanger-in-Black-50-lbs-18015/202305459) (slit vinyl coating with razor and pull off) 5x PC4-M6 [PTFE coupler](https://www.aliexpress.com/item/32814524461.html?spm=a2g0o.productlist.0.0.22fe4a13iG4PKs&algo_pvid=9c6d7534-e71d-4e9b-bbcd-47e6f1801273&algo_expid=9c6d7534-e71d-4e9b-bbcd-47e6f1801273-4&btsid=6382d770-ac95-4a9d-bb2a-b3a1519d41dc&ws_ab_test=searchweb0_0,searchweb201602_1,searchweb201603_53) - make sure to get "coupler" with 4mm bore to pass thru **OR** 5x (or 10x) PC4-M10 [PTFE fittings](https://www.amazon.com/Y