Mechanical Drafter how-to

How to Dimension a Part Drawing Correctly

Good dimensions make good parts.

Updated By the Career Education Institute Curriculum Team
Quick answer

Good dimensions make good parts. In short: pick; dimension; avoid, then complete the remaining steps below.

Step by step

  1. Pick datums.

  2. Dimension from datums.

  3. Avoid duplicates.

  4. Add tolerances.

  5. Add notes.

  6. Check against the model.

Safety reminders for mechanical drafters

  • Wear PPE on shop visits
  • Use ergonomic setups
  • Protect design data
  • Take screen breaks

GD&T · Tolerance · Datum · Assembly · BOM · Section view: see the full mechanical drafter glossary.

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