Laser cut carboard planetary gear

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Build Info:

Gears made using the gear extension in inkscape. The inside gear or ring gear was also made with this extension but I inverted it. I’ll be making a video tutorial on how to do this in the near future. The ring gear has 42 teeth, the 3 ‘planet’ gears have 12 teeth and the central ‘sun’ gear has 18 teeth. This website has lots of useful info on the mechanics and calculations involved in making a planetary gear. The main points to note are:

To get the gears to mesh properly, all teeth have the same pitch/spacing. Also use this equation to calculate the number of teeth required per gear so everything fits correctly:
R = 2 × P + S

R Number of teeth in ring gear
S Number of teeth in sun (middle) gear
P Number of teeth in planet gears

Finally, if you want the 3 ‘planet’ gears to sit at 120 degrees from each other, then both your sun gear and ring gear need to be evenly divisible by the number of planets. Follow these constraints and you are golden!

Design info:

Click here to download SVG file of planetary gear

All line widths in the svg file are set to 0.01mm. Depending on your vector graphics editor the svg file may appear blank when you first open it. You will need to switch to outline mode to see anything. In Inkscape this is done by clicking View > Display Mode > Outline.

Here is a png image of what the svg file drawings look like:
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(Edit)- made another vid just showing the gears rotating…..so…..hypnotic…cant….stop……watching

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