Grade 3 · Tinkercad · Lesson 47

Desk Cable Clip

Measure a model cable and create a small tool that controls its path.

Time2–3 × 60 minutes + adult printingTeamsTeams of 2–3EquipmentTinkercad + Bambu P1S fleet

Project inspiration · 3 images

See, build, and test

Use these images to understand the kind of making, details, and testing involved. They are inspiration—not designs students must copy.

Finished student example for Desk Cable Clip
01Finished project
Close construction and materials view for Desk Cable Clip
02Construction detail
Students testing and recording results for Desk Cable Clip
03Student testing

Student directions · Grade 3

What will you make and do?

You will make a small clip that guides an unplugged model cord along a desk-edge block. The cord should slide in and out without being crushed.

Teacher overview: Students will plan the specific object described below, make and test a first version, then use their results to improve it. Read one step together, demonstrate the unfamiliar action, and let students complete that step before moving on.

  1. 1Plan your project

    Measure the model cord and desk-edge block. Sketch two rounded clip shapes with separate openings for the cord and attachment.

  2. 2Make the first parts

    Try the shapes in foam or clay. Check where the cord enters and whether a user can remove it easily.

  3. 3Put it together

    In Tinkercad, combine a solid body with aligned hole shapes for the two openings. Use the teacher’s fit gaps and minimum thickness before printing.

  4. 4Test it fairly

    Insert and remove the same model cord ten times, then gently draw it through the guide. Record catching, slipping or damage.

  5. 5Improve one part

    Change one opening or rounded edge in the model. Repeat the same cord test; never test with a plugged-in cable.

  6. 6Show and turn in

    Submit the clip, measurement drawing and ten-cycle test record. Explain how its shape guides rather than squeezes the cord.

How will you know it works?

  • Cable enters and exits by hand
  • Guide keeps the cable on its path
  • Edges are rounded and comfortable

Before you move on

Tell a partner what you are making. Point to the part you will work on next. Draw or dictate your test notes if writing slows you down.

Machine cutting, printer setup and electrical power-on require adult approval. A basic-materials model is a valid way to demonstrate the design when equipment is unavailable.

Keep your plan, test notes and before-and-after evidence with the printable design brief below. Use the detailed teacher plan and any coding guide for tool instructions. These steps continue across the lesson’s meetings, not all in one sitting.

For teachers

Engineering standards

This shows how the lesson connects to the national NGSS engineering standards and what student work you can collect.

Assessed

3-5-ETS1-1

Teams define the user or purpose and set measurable size, performance, material, and print-time limits before modeling.

What students show: Problem statement, criteria, constraints, measurements, and labeled sketch.
Practiced

3-5-ETS1-2

Students sketch and compare at least two possible forms before choosing or combining features for the digital model.

What students show: Two ideas and a criteria-based design choice.
Assessed

3-5-ETS1-3

Teams use a repeatable test—insert and remove the same model cable ten times, then gently pull it through the guide—identify a failure point, revise one dimension or feature, and retest.

What students show: Test data, version comparison, and evidence-based explanation.

Materials

  • Unplugged model cords or thick string
  • Cardboard desk-edge blocks
  • Foam and clay clip prototypes
  • Rulers or calipers
  • Graph paper, pencils, cardboard, clay, and tape for prototypes
  • Computer or tablet with educator-managed Tinkercad access
  • PLA filament; teacher sets a project-specific gram and print-time budget
  • Finished test objects appropriate to the lesson

Teacher preparation

  1. Create an educator-managed Tinkercad class and assignment link; students do not enter personal information.
  2. Prepare one navigation demonstration using drag, zoom, orbit, undo, and view cube.
  3. Set the build envelope, minimum wall thickness, minimum feature size, and maximum print time for the class.
  4. Create the file rule G3_47_Team##_v1.
  5. Prepare shared build plates and an adult review queue for dimensions, orientation, stability, material use, and safe slicing.

Step by step

How to teach it

Day 1 · 0–20

Define and measure

  1. Introduce the mission: Design a desk clip that guides the classroom model cable and lets a user remove it easily.
  2. Identify the user, criteria, constraints, and measurements that matter.
  3. Sketch two different solutions at approximately full size.
Day 1 · 20–60

Prototype and compare

  1. Build quick cardboard or clay versions.
  2. Compare both ideas against the shared criteria.
  3. Select or combine features and predict the likely failure point.
Day 2 · 0–15

Tinkercad skill warm-up

  1. Measure the model cable and desk-edge block.
  2. Combine boxes and cylinders into a rounded clip body.
  3. Use aligned hole shapes to create the cable channel and attachment opening.
Day 2 · 15–60

Build the digital model

  1. Place the ruler and enter important dimensions instead of guessing.
  2. Use align and group to create clean, intentional geometry.
  3. Inspect from top, front, side, and underneath; name the file correctly and submit for teacher review.
Day 3

Print, test, and improve

  1. An adult slices, approves, operates printers, and removes parts.
  2. Use the same test procedure each time: insert and remove the same model cable ten times, then gently pull it through the guide.
  3. Revise one dimension or feature in a new Tinkercad version and explain the expected improvement.

Assessment

  • Problem includes a user or purpose plus measurable criteria and constraints.
  • Two sketches show meaningfully different solutions.
  • Tinkercad model uses entered dimensions and purposeful tool choices.
  • Model meets the teacher's printability and material-budget checklist.
  • Test is repeatable and the revision responds to evidence.

Supports & extensions

  • Provide a Tinkercad picture guide and a starter file containing only basic reference shapes.
  • Use mouse practice, larger grid snap, and one new tool at a time.
  • Allow a student to direct a partner or teacher who performs fine cursor movements.
  • Offer measured template objects while preserving choices about form and features.
  • Extension: reduce material, add a moving fit, or create two size variants using parameters recorded on paper.

Safety & responsible use

  • Students do not touch hot ends, heated beds, or moving printer parts.
  • An adult handles slicing approval, printer setup, monitoring, part removal, and support cleanup.
  • Use only lab-approved PLA and teacher-managed accounts; never publish student names or designs publicly without permission.
  • Check finished parts for sharp strings, weak points, and small-piece hazards before use.
  • Printed parts are prototypes—not food-safe, medical, climbing, load-bearing, or life-safety products.

No-machine alternative

Build the final version with cardboard, clay, foam, paper tubes, reusable construction pieces, or teacher-prepared shapes. Keep the same measurements, criteria, fair test, evidence, and revision cycle.

Printable student design brief

The challenge

Design a desk clip that guides the classroom model cable and lets a user remove it easily.

Success criteria

  • Cable enters and exits by hand
  • Guide keeps the cable on its path
  • Edges are rounded and comfortable

Constraints

  • Test model cables only; no plugged-in cords
  • Uses teacher-provided fit gaps
  • No sharp or thin clip arms

Engineer’s notes

Our user needs…
The measurements that matter are…
Idea A and Idea B are different because…
In Tinkercad we used…
Our test showed…
We changed… because…
Our next version would…
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