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04-BS-15 · December 2019

Question 3 of 6: Section View Selection

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

Notes on this paper

National Exams December 2019 — 04-BS-15, Engineering Graphics and Design Process (3-hour, closed-book, no calculator; 6 questions, 100 marks total; all sketches freehand, no straightedge).

Reference texts: Bertoline & Wiebe, Technical Graphics Communication (4th ed.) — orthographic/isometric/section-view theory; Giesecke et al., Technical Drawing / Engineering Graphics (15th ed.) — ASME Y14.5 dimensioning and glass-box projection theory; Ulrich & Eppinger, Product Design and Development (7th ed.); Hibbeler, Mechanics of Materials (10th ed.).

Check: this is a freehand technical-sketching exam with no numerical exam data (dimensions are explicitly stand-ins, "xx", per the exam's own instruction). Every answer sketch for Questions 1–3 was produced by rebuilding the part as a 3-D model from the printed views, then projecting that model with a hidden-line test (a line is dashed only where solid material lies between it and the viewer).

Question 3: Section View Selection (10 marks)

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. See the official exam paper.]

Given: Top View (above) and Front View (below) of a keyed hub on a cylindrical base.

Reading the views. The part is a cylindrical boss on a larger cylindrical base (the two outer circles in the Top View). Its interior is shown only by hidden lines:

Choice of section. Every feature that matters is internal, so a full section is appropriate. The cutting plane is the front-to-back centre plane, A–A: the vertical centre line in the Top View. That single plane passes through the keyway (back), the set-screw hole (front), the bore, the cavity and the slot, so every hidden line becomes a visible one. The section is drawn in the right-side position, and the arrows on the cutting-plane line point in the direction of sight, toward the remaining half.

The obvious alternative is to section the Front View on the left-to-right plane. That would discard the front half of the part, which contains the set-screw hole, and the hole would vanish from the section. A half section is not suitable either, because the part is not symmetric front-to-back: the keyway is at the back and the set-screw at the front.

A A TOP FRONT SECTION A–A FRONT ← → BACK
Q3: Top View with cutting plane A–A, exterior Front View, and FULL SECTION A–A in the right-side position (projected from a 3-D model built from the given views).

Conventions used. One part, so all cut material is hatched at the same 45° angle and spacing, and the boss and base are not hatched differently. Hidden lines are omitted in the section. Visible edges behind the plane are drawn; below the slot roof these are the far slot walls and the cavity wall. The set-screw hole and the keyway are cut by the plane, so they show as gaps in the hatched walls, with the keyway's back edge drawn as a line. The bore and cavity show as open, unhatched space. The axis is drawn as a centre line.