04-BS-15 · December 2014
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Reference texts: Bertoline & Wiebe, Technical Graphics Communication; Giesecke, Mitchell, Spencer et al., Technical Drawing / Engineering Graphics (ASME Y14.5 dimensioning practice, CSA B78.1 Canadian drafting conventions).
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
[Figure not reproduced: Given isometric pictorial: L-shaped stepped block with a hole (same part as Q7). See the official exam paper or the cited reference text.]
A size dimension states how big a single feature is (its own length, diameter, or radius). A location dimension fixes a feature's position relative to a datum edge or another feature, using ordinary linear/angular dimensioning. A coordinate dimension fixes a feature's position using an x/y value read off a common baseline (rectangular datum-dimensioning), useful when many features share the same two datums (e.g. a hole pattern).
Approach. Sketch the front and top orthographic views of the L-block, then label one example of each dimension type: the hole's diameter (size), the step height measured from the base (location), and the hole's centre given as an (x, y) pair from the block's front-left corner (coordinate).
| Dimension type | Example labelled |
|---|---|
| Size | hole diameter ⌀10 mm |
| Location | step height 20 mm from the base |
| Coordinate | hole centre at (35, 20) from the front-left corner datum |
