Question 2 of 6: Isometric View from a Third-Angle Multiview Drawing
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 2: Isometric View from a Third-Angle Multiview Drawing (10 marks)
[Figure not reproduced. See the official exam paper.]
Given: Top View (above) and Front View (below) of a fork-ended link, third-angle.
Reading the views. In third-angle projection the view above is the Top View and the view below is the Front View. The Front View gives the part's true profile, and the Top View shows that the whole profile has one constant depth (thickness):
A fork (clevis) at the left end: two prongs separated by an open, parallel-sided slot that runs through the full depth. A small narrow relief slot continues past the slot bottom. It shows as dashed in the Top View because it lies under the upper prong.
A counterbored cross-hole through both prongs: the stepped dashed rectangles in each prong. The counterbore is on the outer face of each prong: the top of the upper prong and the underside of the lower one. The two share one vertical axis, so a pin can pass through both. The Top View shows the counterbore and hole as two concentric visible circles.
A straight tapered arm ending in a rounded eye. The eye's bore axis is perpendicular to the Front View, so the bore is a circle there and a pair of dashed lines running front to back in the Top View. The solid line in the Top View at the end of the prongs is the edge where the flat top of the prong meets the sloping top of the arm.
Construction. Box in the overall length, height and depth along the three isometric axes, drawn at 120° to one another. Draw the Front-View profile on the front face of the box, transferring every point by coordinates along the axes, including the ends of the sloping taper lines. Then project each corner back through the depth on the receding axis to form the back profile, and keep only the visible edges. The prong counterbore lies in a horizontal face, so it becomes two concentric isometric ellipses on the top of the upper prong. The eye bore lies in the vertical front face, so it becomes an ellipse on that face. The view below is taken from the front-left, which shows the fork opening and the counterbore; a view from the front-right is equally correct.
Q2: isometric view of the fork link, projected from a 3-D model built from the given views (visible edges only).
Check the sketch against the given views: the slot opening, the relief slot and the lower prong's hole should be visible through the fork; the counterbore sits on top of the upper prong; and the eye bore is an ellipse in the plane of the profile, not in the top face.
