The Gusset
Design a gusset to join two 2x1 tubes — matching hole pattern, fillets, and lightening pockets — in Fusion 360.
What Is A Gusset?
A flat plate that ties two tubes into one rigid joint.
- Bolts through matching holes in both tubes.
- Carries load the tube ends can't take alone.
- You will design one this whole lesson.
Open with a real robot photo. Every chassis corner, every arm pivot, every superstructure brace uses gussets. Stress that a gusset turns two weak tube ends into one stiff structure. This is the single most-repeated plate part on the team — get good at it now.
Tube + Hole Pattern
- Standard FRC tube: 2in x 1in x 1/16in wall.
- Holes on a 1/2in grid pattern.
- Holes are #10 clearance (0.196in).
- Pattern is symmetric on both faces.
- Every plate shares the same grid.
- Gussets, bearings, mounts all line up.
- Lets you bolt anything anywhere.
- Match this grid or nothing fits.
This is the most important concept of the lesson. FRC tubing (WCP, TTB, AndyMark) comes pre-drilled on a 1/2in grid with #10 holes. Your gusset MUST place holes on that same grid or it will not bolt up. Show a real tube and point at the hole rows.
New Sketch On A Plane
Create > New Component, name it "Gusset".
- Start a sketch on the XY plane.
- Work flat in 2D first, extrude later.
- Keep the gusset its own component.
Demo Create > New Component FIRST, then sketch. New students sketch straight onto the root — then joints get messy later. One part = one component is the rule all stage. Name it now so the tree stays clean.
Lay Out The Holes
Sketch hole centers on a 1/2in grid.
- Use a Rectangular Pattern of points.
- Set spacing to 0.5in in X and Y.
- Match the count to your tube holes.
Demo sketch point, then Sketch > Rectangular Pattern. Set distance type to spacing, 0.5in. Common mistake: students eyeball hole positions. Force them to dimension the first point off the origin, then pattern. Holes must straddle BOTH tubes to actually tie the joint.
Draw The Outline
Sketch the plate profile around the holes.
- Leave material around every hole edge.
- An L or triangle shape is typical.
- Keep ~0.25in from hole to edge.
The outline must fully enclose the holes with margin. If the edge runs too close to a hole, the bolt will tear out. 0.25in edge distance is a good rule of thumb for #10 hardware. Triangles add stiffness for arm gussets; L-shapes suit drivetrain corners.
Extrude The Plate
Finish sketch, then Extrude the profile.
- Use 0.090in to 0.125in thickness.
- 1/8in (0.125in) is the safe default.
- Extrude as New Body in the component.
1/8in (0.125in) aluminum is the FRC standard gusset thickness — strong, light, water-jet friendly. Thinner 0.090in saves weight on lightly loaded brackets. Show that the holes pattern punches through automatically because we sketched them in the same profile.
Fillet The Corners
Select sharp outer edges, add Fillets.
- Use about 0.25in radius on corners.
- Fillets cut stress and snag hazards.
- Round outside corners, not hole edges.
Sharp corners are stress risers and they cut hands and wires. Modify > Fillet, pick the vertical outer edges, ~0.25in. Tell students NOT to fillet the bolt holes. This is also where a real plate looks professional vs. amateur.
MATCH THE GRID, THEN LIGHTEN IT
Holes on the 1/2in grid make it fit; pockets make it light. Function first, weight second.
Add Lightening Pockets
Sketch pockets in the solid web area.
- Cut partway through or fully through.
- Keep ribs between pockets for strength.
- Rounded triangle holes shed most weight.
Lightening pockets remove material where there's no load path. Cut all the way through for water-jet, or pocket halfway for milled parts. Keep a rib of material around every bolt. Common mistake: pockets too close to holes, leaving paper-thin walls. Leave at least 0.15in of web.
Check Mass & Fit
Set material to Aluminum 6061 first.
- Read mass in the browser Properties.
- Verify holes still land on the grid.
- Confirm edge margins on every hole.
Assign material (Modify > Physical Material > Aluminum 6061) so mass means something. Right-click component > Properties for mass. Have them sanity-check: do holes still sit on the 0.5in grid after all the edits? A great habit before they ever submit a part.
Your Task
- Gusset joining two 2x1 tubes at 90deg.
- Holes on the 1/2in grid, #10 clearance.
- 1/8in aluminum, filleted outer corners.
- At least two lightening pockets.
- Assign Aluminum 6061 material.
- File > Share > Public Link.
- Copy the generated link.
- Paste it on AltHub to submit.
Give them 25-30 min. Walk the room. The #1 fail is holes off-grid — check that first on each student. Second fail is no edge margin. Submission is a Fusion Share public link pasted into AltHub, same as every plate lesson.
🧰 Add-ins for this step
Use the installed AltSkripts / FRC-COTS tools here — don't do it the slow way.
- Bolt Pattern — drop the matching tube/motor hole pattern.
- Fillet All Edges — finish the gusset.
You Designed A Gusset Fit First, Light Second
- Holes on the 1/2in grid = it bolts up.
- 1/8in aluminum, filleted, pocketed.
- Next plate builds on this exact workflow.
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.