Two-Stage Gearbox
Two reductions in one box — plus Part Lighten to cut weight, done at the right time.
01
Two-Stage Gearbox
Stack two reductions for a bigger ratio.
- Layout sketch with two stages: 12T->50T, then 20T->50T.
- Add the motor outlines to the layout.
- Same plate workflow, more gears.
FUSION 360 · SCREENSHOT
add → course-shots/1b-07/1.png
FIG 1
02
Build the Plates
Same plate recipe, scaled up.
- Bearing holes 1.125 in, motor bosses 1.25 in, mounting holes.
- Extrude plates to 1/4 in.
- Make the spacer, input shaft, and output shaft with AltSkripts.
FUSION 360 · SCREENSHOT
add → course-shots/1b-07/2.png
FIG 2
03
Pocket & Lighten
Cut weight once the design is locked.
- Sketch pocketing ribs for the lightening pattern.
- Run AltSkripts Part Lighten to remove material.
- Strength stays where the ribs are.
FUSION 360 · SCREENSHOT
add → course-shots/1b-07/3.png
FIG 3
Key idea
Lighten only a finished design.
Weight-saving is the last step, not the first.
Recap
TWO-STAGE GEARBOX
- Two stages: 12T->50T, 20T->50T
- Same plate workflow, 1/4 in thick
- Shafts/spacers via AltSkripts
- Part Lighten LAST, after review
Your Task
Build this
- Model what this lesson covers in Fusion 360.
- Use the AltSkripts tools where they apply.
- Save it with a clear name.
How to submit
- In Fusion: Share → Public Link → Copy.
- Paste the link below.
- A coach reviews it in AltHub.