04-BS-15 · December 2018
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Basic Studies / 04-BS-15 — Engineering Graphics & Design Process, December 2018. Closed-book, no calculator, 3 hours, 100 marks; five questions constitute a complete exam paper (answer ALL five). All sketches are freehand technical drawings following third-angle projection (CSA B78.1 / ASME Y14.5) unless the question calls for isometric pictorial or sectioning conventions.
Reference texts: Bertoline & Wiebe, Technical Graphics Communication (4th ed.) — orthographic projection, isometric pictorials, auxiliary/section views, third-angle projection; Giesecke, Technical Drawing / Engineering Graphics (15th ed.) — ASME Y14.5 dimensioning, CSA B78.1 drafting practice, sectioning conventions, glass-box projection theory.
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 and orthographic views of the bossed plate. See the official exam paper or the cited reference text.]
Given. The pictorial and the three views (TOP upper left, FRONT and RIGHT SIDE below) show a rectangular plate with a stepped underside: it is full thickness over the left part and thinner on the right. This appears as the dashed line in TOP, the step in the bottom outline of FRONT, and the horizontal line in RIGHT SIDE. The plate carries three features. (1) A cylindrical boss with a fillet at its base and a through-hole that is countersunk at the top: the “\ /” at the top of the boss hole in FRONT and RIGHT SIDE, and the two inner circles in TOP. (2) A small counterbored through-hole near the front-left corner: the short, wide hidden rectangle at the top of the plate over a narrower hidden hole in FRONT. (3) An obround through-slot in the thin right-hand portion, near the back. The three features lie on three different front-to-back lines: the small hole is nearest the front, the boss is next, and the slot is nearest the back.
No single straight cutting plane passes through all three internal features, so an offset section is the appropriate choice. The cutting plane A-A runs along the centre of the counterbored hole, steps back at right angles through the axis of the boss, and steps again along the long axis of the slot. Each step is placed in solid material, clear of every feature. The section is projected as the FRONT view, with the arrows showing the line of sight (toward the back). In the section: all cut material is hatched with one uniform 45° pattern, because it is a single part. The offsets are not drawn, since an offset section is drawn as if the plane were flat. The section shows the counterbore, the boss with its countersink, through-bore and base fillets, the slot opening in the thin portion, and the underside step. Hole and slot openings are left unhatched. Visible edges beyond the plane are drawn (the tangent lines at the far end of the slot); hidden lines are omitted. A full section through the boss axis alone would also be a valid section but would miss the counterbore and the slot. A half section does not suit this part because it is not symmetric.
The cutting-plane line is drawn as a thick long-dash/double-short-dash line, with arrows and the letter A at each end. Section lines are thin, uniformly spaced and at 45° to the main outline (ASME Y14.2 / CSA B78.1). Centre lines mark the hole and boss axes in the section.
