Introduction: Trying to Make JorgeD78 Rotocaster

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I tried making the rotocaster of this instructable: https://www.instructables.com/Rotomoldeadora/ but I wanted a lot of clarification for certain parts so I wanted to document things I did to make the rotocaster in 2022. I'll walk through some problems I had with the files and with assembly so that maybe one day someone will make a fix? DISCLAIMER: I didn't complete the rotocaster NOTE: this not a step by step instructable, just issues I had when building the rotocaster that might help another person. This is for a class btw.


Last updated: 12/10/2022

Supplies

I used:

  • a Shapoko 3 XL CNC Router
  • MDF Boards (details needed)
  • Lulzbot 3D Printer + Cura Lulzbot
  • PLA to work the 3D Printer
  • 16 Wood screws (4 3/4" screws and 12 1" screws, you can also get em longer than 1")
  • 8 (608) bearings
  • 1/4 coarse threaded rod (3ft or 1m)/better if you get more than intended, just in case you need to cut off more
  • an angle grinder
  • bunches of 1/4" coarse nuts
  • 4 Hex Tap Bolt 5/16"x2"
  • 1 Hex Tap Bolt 5/16"x6"
  • 32T to 11T(?) bicycle cassette that separates each gear
  • bicycle chain

Step 1: The Files (3D Prints)

While trying to print the 3D printed parts not all of the stl could fit onto the Lulzbot that I had access to. So I separated the stl's into thirds so you dont have to. To make them, I imported them into blender and delete vertices in order to make these, if you need to break them down even further.

Attachments

Step 2: The Files (CNC)

I also had the same problem with the CNC Files since the Shapoko did not fit the size of the CNC. I separated these into thirds as well.

If you're in the US like me, my MDF boards do not come in 15mm, so i used 1/2" MDF boards instead.

Attachments

Step 3: Assembly (3D Prints)

While putting together the rotocaster I was met with a few problems, though I think a few can be attributed to me tweaking the files. One is that the 3D Printed parts were too big to be a tight fit on the MDF portions. All of the wood screws were left hanging on the other side of the board. I was able to make sure the rotocaster still stood but I'm not exactly sure how to fix that. The opposite problem did happen with the part that uses two halves to attach itself to the smaller rectangle's top and bottom. Those actually required me to sand the sides in order for them to fit. I also hammered them into the board so that they could fit in, and the plugs broke </3. I feel that something can be done to make that part better, but I'm not an engineer.

Step 4: Assembly (nuts and Threaded Rod)

Despite what is written in the instructions the rotocaster actually requires two sizes of threaded rod: 5/16" and 1/4". I didn't want to waste 5/16" threaded rod I was not going to use later, so I opted for 5/16" hex tap bolts. You only need these for the bottom portion of the rotocaster on the two support pieces that hold up the rotocaster and the handle part connected to the rotocaster (which is the 6" one). They connect to the 3D printed piece at the bottom of it horizontally. The rest of the build that needs threaded rod is all 1/4". I marked the lengths I needed in sharpie and cut them to shape on an angle grinder. The person in the photos used a dremel, and im not sure how safe that is... but if you dont have an angle grinder but have a dremel ig you can use that too.

Step 5: Bearings

I bought 608 bearings bc people told me that's what fit in them. It did not fit. I had to sand down the inside of the 3D printed parts for them to barely fit. If anyone knows like a size of bearing thats like 1mm smaller than a 608 please buy those. I thought when I put in the bearings in the rotocaster would rudimentarily work but it DID NOT. Not sure how the bearings worked with the threaded rod and nuts because those hex nuts kept wriggling around and def did not hold in place for the bearing to work.

Step 6: Gears

So I noticed in the lil pictures that the person took apart a bike cassette and used the sprockets to make the contraption turn. I did buy a cassette but im not sure how they're supposed to fit because the holes do not line up with holes made in the 3D part for the big gear. I believe the size is 32T for the big gear so if you know how to drill the smallest holes in metal go for it!

I know bike cassettes come attached to each other but I think some brands can let you take individual gears out! I don't know how you take the individuals out though.

The only thing I really do not know is the lil gear at the top of the rotocaster bc i bought a cassette that was 32T to 11T and 11T was too big for the threaded rod. Its a gear thats such a mystery to me. What is it called. Where can I get it.

That gear is the only thing preventing me from completing this rotocaster!!