3D printed, 608 full spec, planetary gear bearing. The 608 is also known as skateboard bearings. Good for prototyping (before using real 608 bearings) and for light load jobs.
You can see a video of it in action here: https://youtu.be/X48_UYtfMCs
- 19-teeth sun
- 31-teeth annulus or ring gear
- 10 6-teeth planets
- 0.15 tolerance
As per 608 specs:
- 22 mm diameter
- 7 mm thickness
- 8 mm bore .
3 different 608 bearings:
- round outer race and inner bore (typical 608)
- square outer race (22 mm) and inner (6 mm) bore
- hex outer race (22 mm) and inner (8 mm) bore
Square and hex break-in tools:
- outer race holder
- inner bore key, with triangular shaft for a drill's 3-jaw chuck and a hole for a pencil or screwdriver to give you extra leverage.
I give credit to Gear God emmett, I used his customizer to spec it to 608. His branding had to go though, it had a few holes.
Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=53451
Printed in a SeeMeCNC Rostock Max V2 with E3D V6:
- 0.25 mm nozzle hot end
- 0.095 layer height
- ~2 hours
- ABS though it should be printed with nylon for the best performance
Somebody printed it with .4 mm nozzle, which is good as most OEM nozzles can print it and faster.
Since it sliced to 74 layers, I set it up with 37 top and 37 bottom solid layers, 0% infill, and only 1 perimeter; it's solid.
Lapping (smoothing the parts that contact)
Lapping with a drill, using the included tools, makes it smoother, it gets warm but I think it helps. I lapped it for 2 seconds with the drill AND coarse abrasive compound, and it is now very smooth, though coarse abrasive may be too much as it introduced more axial play; will test fine abrasive compound.
Depending on the application, a little bit of lithium grease could work? Will test this, too.
You need to free the gears, but it does turn, though it is rough. Could be broke-in better with the tools included. A tool for the round bearing is in the works.
Customized using the following options:
w = 7
P = 45
T = 7
D = 22
tol = 0.15
number_of_teeth_on_planets = 6
approximate_number_of_teeth_on_sun = 20
nTwist = 1
number_of_planets = 10