Practice: Capstone
Capstone practice: combine subsystems into one complete mechanism, applying everything from Stages 1A and 1B
The Capstone Challenge
Design one complete mechanism, start to finish.
- Pick a subsystem: intake, shooter, arm, or gearbox.
- Use everything from Stages 1A and 1B.
- No step-by-step guide this time.
- You own the design decisions.
Frame this as the payoff for the whole stage. Up to now every exercise had a recipe. Now they get a goal and the toolbox, and they choose the path. Reassure nervous students: scope small and finished beats big and broken. This is exactly how real FRC CAD starts.
Choose One Subsystem
- Roller intake: 2x1 frame + NEO + #25 chain.
- Flywheel shooter: Kraken + 4in compliant wheels.
- Single-jointed arm: pivot on dead axle + gearbox.
- Indexer: powered rollers feeding a shooter.
- Keep it to 1-2 moving subsystems.
Push them to pick something they can actually finish in the class window. The roller intake is the safest first capstone. Discourage swerve drivetrains or full elevators here, those come in Stage 2. If a student is unsure, assign the roller intake.
Sketch Before You Model
Draw a rough layout sketch on paper first.
- List the subsystems and how they connect.
- Decide motor, reduction, and frame size early.
- Note which parts you'll insert vs model.
- Set User Parameters for key dimensions.
The number one capstone failure is diving into Fusion with no plan. Make them sketch the side view on paper and label the motor, reduction, and frame. Remind them to set User Parameters (Modify > Change Parameters) for things like tube size and gear reduction so changes propagate.
Start With Structure
- Model the 2x1 tube frame as components.
- Use Joints, not just position, to assemble.
- Insert COTS: NEO/Kraken, bearings, MAXSwerve.
- Name every component in the browser tree.
- Save often to the cloud Data Panel.
Have them build the structural frame first, then hang mechanisms off it. Each tube should be its own component. Stress correct Joints: revolute for the roller axle, rigid for brackets. Common mistake: leaving everything as bodies in one component so nothing can move or be reused.
Add The Power Transmission
- Mount the motor on a plate or bracket.
- Add reduction: 20DP gears, #25 chain, or 5mm HTD.
- Put the driven shaft on 1/2in hex.
- Check bearing bores match the shaft.
- Use SpurGear add-in for gear bodies.
This is where Stage 1B pays off. Make them justify their reduction with a rough torque/speed number, not a guess. Remind them 1/2in hex is the FRC standard shaft and bearings must match. The SpurGear add-in generates correct 20DP tooth profiles fast.
DONE BEATS PERFECT
A small mechanism that fully assembles and moves is worth more than a huge one that doesn't.
Test Your Joints
Drag the joint to confirm motion is right.
- Roller spins, arm pivots, slider slides.
- Check for collisions through full range.
- Fix any parts that move together wrongly.
- Ground exactly one base component.
Have them grab the revolute joint and rotate it through full travel. This catches the classic mistake of a joint on the wrong origin or axis. Exactly one component should be grounded (the frame). If the whole assembly flies apart when dragged, a joint is missing or mis-typed.
Acceptance Criteria
- Multiple named components, not loose bodies
- Real Joints (revolute/slider/rigid)
- At least one COTS part inserted
- One subsystem powered by a motor
- User Parameters drive key dimensions
- Reduction matches motor and goal
- No collisions through full motion
- Clean, organized browser tree
Walk through this as a checklist before anyone submits. Tell them to literally tick each item. The MUST HAVE column is the pass bar. The SHOULD HAVE column separates a good capstone from a great one. Anything failing the left column gets sent back.
Your Task
- One mechanism, fully assembled with Joints
- Frame + at least one powered subsystem
- Meets every MUST HAVE criterion
- Demonstrate it moving via a joint
- File > Share > Public Link in Fusion
- Copy the generated share URL
- Paste the link on AltHub
- Add one line: what mechanism + motor
This is the graded deliverable. Show them File > Share and how to toggle the public link on, then copy it. They paste it into the AltHub training module with a one-line description. Set a clear deadline. Offer to review one work-in-progress link mid-week so nobody submits something broken.
Common Capstone Mistakes
- Everything modeled as bodies in one component.
- No Joints, so nothing actually moves.
- Reduction picked with no torque reasoning.
- Bearing bores that don't match 1/2in hex.
- Scoping too big and never finishing.
Run through these fast so they recognize their own work. The single-component trap is by far the most common. Second is forgetting joints entirely. Catch these in your mid-week review. Reassure them mistakes are expected, that's why this is practice before Stage 2.
You Built A Real Mechanism Now Ship It
- Plan on paper, build frame, power it, test joints.
- Meet every MUST HAVE before you submit.
- Share > Public Link, paste on AltHub.
Your Task
- Model what this lesson covers in Fusion 360.
- Use the AltSkripts tools where they apply.
- Save it with a clear name.
- In Fusion: Share → Public Link → Copy.
- Paste the link below.
- A coach reviews it in AltHub.