Harbor Freight Rock Tumbler Improvements

After my son got a rock tumbler for Christmas, our interest was sparked enough to end up purchasing the Harbor Freight rock tumbler (Central Machinery). This rock tumbler has many flaws but with some 3d printing and a little know how, we've overcome them. The tumbler should last for years now.

Here are the mods:

1. I no longer recommend the the roller wheel upgrade. Instead just use a single sticky back furniture pad / floor protector. Cut it in half and place a half at each end of the frame where the barrels roll. This is much more effective and makes it easier to swap barrels in/out. https://www.amazon.com/dp/B082VJDK44?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2&th=1 Change the plastic barrel stops to a roller wheel. This keeps the barrels from grinding on the frame.

   1. The roller is not my part, but I'm going to include for convenience. Here is a link to it on Thingiverse : https://www.thingiverse.com/thing:2054092/makes. The original designer goes by "Plastic_Innovations" on thingiverse.

   2. Here are the shower door wheels I used on the roller for the drum: https://www.amazon.com/dp/B09V2MN4B3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 " 19mm Replacement Part Bathroom Glass Runner Sliding Shower Door Roller Wheel"

2. Swap the bushings for bearings. This requires drilling out the holes in the frame to accommodate the bearings. Use a step bit for this and be careful not to make them too large. 

   1. Installing the bearings requires drilling the bushing holes in the frame out to 16mm or 5/8th inch. Here are the bearings I ordered for this: https://www.amazon.com/dp/B07Z3F68H4?ref=ppx_yo2ov_dt_b_fed_asin_title "uxcell F688ZZ Flanged Ball Bearing 8x16x5mm Shielded Chrome Steel Flange Rip" After I drilled the holes, I found that a bearing sleeve might be necessary so I measured and printed some custom ones based on the holes I drilled.

3. Replace the motor cover with a 3d printed one to accommodate a new muffin fan. This keeps the motor (which runs hot) very cool. I added this to the switch so it turns on/off with the unit.  

   1. Here is the fan I ordered for the project: https://www.amazon.com/dp/B07SB5K555?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 "Wathai EC Brushless Cooling Fan AC 110V 115V 120V 220V 240V Axial Fan Ball Bearing 60mm x 25mm"

I printed all these parts in Prusament PC-Blend for strength and heat tolerance but after using it for a while I imagine that PLA would do just fine. I printed most parts more or less solid with many walls (Up to 5). The motor cover can be printed with fewer walls. I reuse the bottom spacer for the motor cover that comes on the rock tumbler originally, I just replace the top with a custom one made to fit a fan and I added some slots for ventilation.