Sun & 4 Planets

The idea for this gearset came from the following posting I saw online:

https://parametrichouse.com/gears/

Since I use Grasshopper to make all my designs I thought I could use this method to make a small gearset that would be a nice demonstration of the Planthopper software add-on to Grasshopper. So I installed it and started working.

Well, it turned out it was more complicated than I expected. Planthopper was made to produce precisely machined metal gears. It does not account for the dimensional inaccuracies inherent with all 3D printers and their printed results. So I had to make several adjustments to get a good result. Plus I had to add a handle to one of the gears to make the whole assembly easily workable. The STL files included here are the final result.

Here's how to get everything working OK:

1. Print the base. This is a simple print that holds the gears in the proper orientation.

2. Print child.stl. This will produce just the 4 child/planet gears. They will print if the orientation they will have on the base, but you can move them around in your slicer any way you want. Just make sure there is some space between them.

3. Print main.stl. You can print this one separately, or along with child.stl, but make sure it is spaced away from all the child gears if you do.

4. With everything printed, assemble the gears on their appropriate posts. First, fit the child gears on their posts. It will be a tight fit, but they will fit with enough clearance to spin properly. Spin each gear by hand to work out and sticking points. This should only take a minute or so.

5. With the 4 child gears in place, fit the main gear on it's post. You'll have to manually line up the teeth on each child gear. Then spin the main gear by gripping its teeth (not the handle) until every thing works fairly smoothly. Once the gears work smoothly enough to use the handle it will still take a while to get all the gears turning as smoothly as you like.

Once all the sticking points are worked out all the gears will turn freely and you can crank the handle as fast as you like.