Engineering drafting for intermediate users

Dimensioning, tolerances and fits, and section and auxiliary views.

3 lessons · about 1 hours · free

Defining parts

1. 1. Dimensioning principles

   Dimensions define size and location. Good dimensioning is complete, not duplicated, based on function, and arranged so tolerances don’t accumulate unexpectedly.

   • • Dimension parts completely without duplication
   • • Dimension from functional datums
   • • Choose between chain and baseline dimensioning

   20 min

2. 2. Tolerances and fits

   No part is made exactly to size. Tolerances state how much variation is acceptable — and fits define how mating parts go together. Learn to read and specify them sensibly.

   • • Explain why tolerances are needed
   • • Read and write limit and ± tolerances
   • • Use general tolerance notes

   20 min

3. 3. Sections and auxiliary views

   Hidden lines get confusing fast. Section views cut parts open to show internal features, and auxiliary views show inclined faces in true shape.

   • • Choose the right section type
   • • Apply hatching conventions
   • • Know what isn't sectioned

   18 min