Mechanical Drafting, GD&T and Jig Design Terms
A glossary for people who make and read drawings. It covers 149 terms: meaning, how to write them on a drawing, examples, common mistakes, and where JIS and ASME (US) differ. Also see the checklist (65 items)to review before releasing a drawing.
Before releasing a drawing,
check it against the
checklist!
Drafting Basics (40 terms)
Projection methods, choosing views, line types and their uses, section views, rules for simplified drawing, title block.
≡Dimensions and Tolerances (17 terms)
Dimensioning rules, dimensional tolerances, fits, general tolerances, and how to dimension to avoid accumulation.
⌖Geometric Tolerancing (46 terms)
The 14 geometric characteristics, tolerance frame, datums, maximum material requirement, projected tolerance zone, common zone, TED.
√Surface Texture (7 terms)
Surface texture symbols, placement of requirements, and how to write Ra and Rz.
≡Drawing Features (11 terms)
How to draw part features such as threads, holes, counterbores, gears, and welds.
≡Machine Design (12 terms)
Design rules such as choosing fits, chamfers and reliefs, and shapes that are easy to machine.
⊥Jig Design (16 terms)
The 3-2-1 principle, reference surfaces, locating pins and diamond pins, clamping principles, bushings, poka-yoke (error proofing).
✓Checklist before drawing
65 items covering the whole drawing, lines, dimensions, tolerances, geometric tolerances, surfaces, manufacturability, assembly, and jigs. You can tick them off and print the list.