Filament Loader for Multiple Mechanism Auto-Rewind Spool Holder

Recently some friends and I have installed the Prusa Multi-Media Unit (MMU2) on our printers. I was struggling with the filament 'buffer' that came with it. It was difficult to load and only marginally effective at capturing the filament when unloading it.

I tried several different Spool Holder designs and settled on the ‘Multiple Mechanism Auto-Rewind Spool Holder’ (https://www.thingiverse.com/thing:3691892). Using it I was able to eliminate the Prusa filament buffer. My only problem was it was painful loading the filament between the spool and the MMU. I used a 1/2 inch by 1 inch long bolt and two nuts for the rack weight, but a friend tried a 1/2 inch by 2 inch long bolt with 3 nuts, which he felt worked better.

My solution to make loading the filament easier, adds a manual extruder mechanism that I can lock and crank, to push or pull the filament between the spool holder and the MMU.
https://youtu.be/Q5-BetxFkDU

I haven't tried it, but you should be able to glue the winder and the extruder to an existing spool holder.

It uses a 5mm steel ball and a spring that I hand wound from piano wire as a detent for the Base Winder Cam to hold the Base Winder Lock Lever in position.

A PC4-M6 Fitting can be screwed into the Base Winder Main to hold the PTFE tube to the MMU.

Here are some of the parts that I used:

WINSINN MK8 Drive Gear Extruder Hotend Feeder 40 Teeth 5mm Bore Stainless Steel for CR-10 CR10 Prusa I3
https://www.amazon.com/gp/product/B077GP454R/ref=ox_sc_act_title_1?smid=A2QQQKMKGVNA5E&psc=1

HUABAN 10pcs 3D Printer MK8 U604ZZ 604UU 4x13x4mm U-Shaped Bearing Extruder Round Wheel Gear Walking Guide Rail Bearings Fitting Pulley
https://www.amazon.com/gp/product/B076D67T6V/ref=ox_sc_act_title_2?smid=A1G4TRJSF885ET&psc=1

Eowpower 10Pcs 100mm x 5mm Ground Shaft Round Rod for RC Helicopter Airplane Car
https://www.amazon.com/gp/product/B079KQ294C/ref=ox_sc_act_title_3?smid=A1M8G92U41XEUX&psc=1

All the screws are M2x10 flat head, except for those noted on the figures.

I provided Rack Side B a and b STLs as an alternative to printing Rack Side B laid down as one piece. Print Rack Side B a STL with supports, and Rack Side B b without, then glue them together with Acrylic Cement.

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