From Part to Assembly: A Robot Bracket

A bracket is a small part whose only job is to hold one thing on another, such as a sensor on the chassis or a pivot for a short arm. It looks simple, but it only works if its holes line up exactly with the kit structure. In this lesson you design one, then prove in an assembly that it fits before anyone cuts or prints it.

Step 1: Get the real numbers first

• Hole spacing (pitch): the distance between hole centres on your kit's channels, plates or extrusions.
• Hole size and screw size: which screws the kit uses and what size the holes are.
• Material thickness: needed later to choose screw length.
• Where you found it: write the document or product page name next to each number in your notebook.

Step 2: Model the bracket

1. 1
   Variables first

   In a new Part Studio named Bracket, create variables such as pitch, holeDia and thickness with the values from your notes.
2. 2
   Sketch the plate

   Sketch a rectangle large enough for at least two kit holes plus the part you want to hold. Fully define it.
3. 3
   Place hole points

   Add points for the kit holes and dimension the distance between them as #pitch (or a multiple, such as 2 * #pitch). Add separate points for the component's own mounting holes, using its datasheet.
4. 4
   Make it solid

   Extrude by #thickness, add simple through holes of #holeDia on the kit points, and fillet the corners.

Step 3: Build the assembly

1. 1
   Bring in the kit part

   Create an Assembly tab. Add the vendor's model of one channel or plate, either by importing a STEP file with Import or with Insert from a public vendor document.
2. 2
   Fix it

   Right-click the kit part and choose Fix, so it stays put while everything else attaches to it.
3. 3
   Insert your bracket

   Use Insert, open the current document and pick your bracket part. It stays linked: edits in the Part Studio appear here automatically.
4. 4
   Fastened mate

   Choose Fastened mate, hover over a bracket hole until a mate connector appears at its centre, click it, then click the matching kit hole. Flip the direction if the bracket lands upside down.
5. 5
   Revolute mate

   Add a short practice arm part, then connect it to a bracket hole with a Revolute mate. Drag the arm and watch it swing. Set limits in the mate if it should only turn part of the way.

Step 4: Check fit and interference

• Hole alignment: use the Measure tool between a bracket hole edge and the kit hole edge. Both mated holes should share the same centre line.
• Clashes: turn on clash detection in the assembly, or create a section view through the screws, and look for parts overlapping.
• Motion: drag the revolute part through its whole range and watch for collisions with the frame.
• Tool access: check there is room for a screwdriver or hex key and for the screw heads and nuts.
• Making it: 3D printed holes often come out slightly small, so test print a small piece before printing the full bracket.

Step 5: Save a version and share it

1. 1
   Create a version

   Click Create version in the top toolbar. Give it a clear name such as Bracket V1 fits channel and a one-line description of what was checked.
2. 2
   Share view-only

   Click Share, add teammates and choose Can view. Keep edit access for the students who are designing this part, so nobody changes it by accident.
3. 3
   Point to the version

   Ask the team to open the named version from the version history so builders work from a fixed snapshot rather than a model that is still changing.