CBSE Class 12 Engineering Graphics — NCERT Solutions

Given:

• Base edge of triangular prism = 65 mm
• Axial height (length) = 85 mm
• Resting on one of its rectangular faces on H.P.
• Base (triangular face) perpendicular to V.P.

Concept: When a triangular prism rests on one of its rectangular faces, its axis lies horizontal (parallel to H.P.) and perpendicular to V.P. We use the box method to draw the isometric projection.

Steps:

Step 1 – Draw the isometric box:
Draw an isometric rectangular box of dimensions:

• Length (along axis) = 85 mm (along the receding isometric axis toward V.P.)
• Width = 65 mm (along the left isometric axis)
• Height = height of equilateral triangle with side 65 mm

$$h = \frac{\sqrt{3}}{2} \times 65 \approx 56.3 \text{ mm}$$

Step 2 – Locate the triangular base:
On the left vertical face of the box (which represents the plane perpendicular to V.P.), mark the equilateral triangle:

• Let the bottom-left and bottom-right corners of the rectangular face be $A$ and $B$ (65 mm apart along the base).
• Find the apex $C$ at the midpoint of $AB$, raised by $h \approx 56.3$ mm vertically.

Step 3 – Draw the prism:

• Project all three vertices $A$, $B$, $C$ of the triangular base along the axial direction (85 mm) to get the other triangular face $A'$, $B'$, $C'$.
• Join $AA'$, $BB'$, $CC'$ as the lateral edges.
• Draw the two triangular faces and the three rectangular faces (only visible faces with thick lines; hidden edges as dashed or omitted per convention).

Step 4 – Complete the drawing:

• Mark the axis of the prism as a chain-dash line along the 85 mm direction.
• Add dimensions: base edge = 65 mm, axial height = 85 mm.
• Show the direction of viewing arrow.
• Use thick lines for visible edges and conventional lines for axis and centre lines.

Result: The isometric projection of the triangular prism resting on its rectangular face is complete.

Given:

• Base side of pentagonal prism = 35 mm
• Axial length = 60 mm
• Resting on one of its face edges on H.P.
• One rectangular face parallel to H.P. (on top)
• Axis perpendicular to V.P.

Concept: The prism rests on a bottom edge of one rectangular face; the axis is horizontal and perpendicular to V.P. (going into the picture). The top rectangular face is horizontal (parallel to H.P.).

Steps:

Step 1 – Draw the helping figure (true shape of pentagonal base):
Draw a regular pentagon of side 35 mm with one side at the bottom (resting edge) and one side at the top (parallel to H.P.).

• Label the bottom edge vertices as $A$ (left) and $B$ (right).
• The remaining three vertices going upward: $C$ (bottom-right), $D$ (top), $E$ (bottom-left) — following the pentagon.
• The top side is $DE$ (parallel to H.P.).

Step 2 – Set up isometric axes:
Since the axis is perpendicular to V.P., the pentagonal faces appear on the left and right isometric planes. The 60 mm length goes along the receding (depth) isometric axis.

Step 3 – Draw the front pentagonal face:
On the left isometric plane (vertical plane perpendicular to V.P.), draw the pentagon:

• Draw base edge $AB = 35$ mm horizontally.
• Construct the remaining vertices using true measurements transferred along isometric vertical and horizontal directions.
• Mark all five vertices of the pentagon.

Step 4 – Project to get the rear face:
Project each vertex of the front pentagon 60 mm along the receding isometric axis to obtain the rear pentagonal face $A'B'C'D'E'$.

Step 5 – Draw visible rectangular faces:

• Top rectangular face ($DD'E'E$): parallel to H.P. — draw with thick lines.
• Two side rectangular faces visible from the viewing direction.
• Bottom resting edge $AB$ and $A'B'$ on H.P.

Step 6 – Complete the drawing:

• Draw the axis as a chain-dash line along the 60 mm direction.
• Add dimensions: base side = 35 mm, axial length = 60 mm.
• Show direction of viewing arrow.
• Use thick lines for all visible edges.

Result: The isometric projection of the pentagonal prism resting on one face edge with top face parallel to H.P. is complete.

Given: Scale 1:1, Pitch P = 30 mm (enlarged), BSW (British Standard Whitworth) thread profile.

Standard proportions of BSW thread:

• Pitch P = 30 mm
• Depth of thread: $d = 0.6403P = 0.6403 \times 30 \approx 19.2$ mm
• Radius at crest and root: $r = 0.1373P = 0.1373 \times 30 \approx 4.1$ mm
• Flank angle: 55° (i.e., included angle = 55°, each side = 27.5° from vertical)

Steps:

1. Draw a thin horizontal centre (axis) line.
2. Mark pitch divisions of 30 mm along the axis.
3. Draw the crest line (outer boundary) and root line (inner boundary) parallel to the axis, separated by the depth $d \approx 19.2$ mm (half on each side = 9.6 mm from axis).
4. Draw the flanks at 27.5° to the vertical (included angle 55°) connecting crest to root.
5. Round off the crests and roots with radius $r \approx 4.1$ mm using a compass.
6. Apply hatching and mark all standard dimensions: P = 30 mm, depth = 19.2 mm, r = 4.1 mm, flank angle = 55°.

Final Answer: The BSW thread profile is a V-thread with 55° included angle, rounded crests and roots (r = 0.1373P ≈ 4.1 mm), and depth = 0.6403P ≈ 19.2 mm, drawn to scale 1:1 with P = 30 mm.

Given: Scale 1:1, Pitch P = 60 mm (enlarged), Metric external thread (V-thread, 60° included angle).

Standard proportions of Metric thread:

• Pitch P = 60 mm
• Depth of thread (theoretical): $H = 0.866P = 0.866 \times 60 = 51.96$ mm
• Actual depth (external): $d = 0.6134P = 0.6134 \times 60 \approx 36.8$ mm
• Crest: flat = $P/8 = 60/8 = 7.5$ mm
• Root: flat = $P/4 = 60/4 = 15$ mm (or rounded)
• Flank angle: 30° each side (included angle = 60°)

Steps:

1. Draw a thin horizontal centre line (axis).
2. Mark pitch divisions of 60 mm along the axis.
3. Draw crest line and root line parallel to the axis; total depth = 0.6134P ≈ 36.8 mm.
4. Draw flanks at 30° to the vertical on each side (60° included angle).
5. Truncate the crest with a flat of P/8 = 7.5 mm and the root with a flat of P/4 = 15 mm.
6. Apply hatching and dimension: P = 60 mm, depth ≈ 36.8 mm, crest flat = 7.5 mm, root flat = 15 mm, included angle = 60°.

Final Answer: Metric external thread profile — 60° V-thread, depth ≈ 36.8 mm, crest flat = 7.5 mm, root flat = 15 mm, drawn to scale 1:1 with P = 60 mm.

Given Information:

• Assembly: Open Bearing
• Parts: Body (Cast Iron) – 1 off, Bush (Gun Metal) – 1 off
• All fillets and rounds = R5
• Scale: 1:1
• Projection: First Angle

Step 1 – Understand the Parts

Body (C.I.):

• A rectangular base/pedestal with a semi-circular (open-top) seating at the top centre to receive the bush.
• The base has bolt holes for fixing to a surface.
• Typical overall dimensions (read from detail drawing): Base length ≈ 100 mm, Base width ≈ 60 mm, Height ≈ 60 mm, Bore (semi-circular seat) diameter ≈ 50 mm.

Bush (G.M.):

• A half-cylindrical (semi-circular) bush that sits in the open seat of the body.
• Outer diameter matches the seat in the body (≈ 50 mm), Inner diameter (bore) ≈ 25 mm.
• The bush is a plain half-bush (open bearing type — no cap).

Step 2 – Assembly Principle

The Gun Metal bush is placed into the semi-circular recess of the Cast Iron body. The shaft rests on the inner bore of the bush. Since it is an OPEN bearing (no top cap), the bush simply sits in the body's open seat.

Step 3 – Drawing Procedure

(a) Front View – Left Half in Section:

1. Draw the outer profile of the assembled bearing in the front view (full external view on the right half).
2. On the LEFT half, draw a sectional view by cutting along the vertical centre plane (plane of symmetry).
3. In section, show:

• The C.I. body: hatch with Cast Iron hatching (evenly spaced 45° lines).
• The G.M. bush seated in the body: hatch with Gun Metal hatching (closer spaced 45° lines, or cross-hatching as per convention).
• The semi-circular bore of the bush (inner hole) is visible.

4. Show fillets R5 at all internal corners.
5. The base of the body shows the bolt holes (shown as hidden lines on the right half, or in section on the left half).

(b) Left Side View:

1. Project the Left Side View from the Front View.
2. Show the full external profile of the body from the left side.
3. The semi-circular open top of the body is visible.
4. The bush (half-cylinder) is visible sitting in the seat.
5. Show the base plate outline, bolt holes as circles (or hidden lines).
6. All visible edges are drawn as continuous thick lines; hidden edges as dashed lines.

Step 4 – Six Important Dimensions to be Marked

$$\text{1. Overall length of base} = 100 \text{ mm}$$
$$\text{2. Overall width of base} = 60 \text{ mm}$$
$$\text{3. Overall height of body} = 60 \text{ mm}$$
$$\text{4. Bore diameter of bush (shaft hole)} = \phi\,25 \text{ mm}$$
$$\text{5. Outer diameter of bush / seat diameter} = \phi\,50 \text{ mm}$$
$$\text{6. Bolt hole diameter and pitch} = \phi\,10 \text{ mm, PCD or spacing as given}$$

Step 5 – Title Block and Projection Symbol

• Title: OPEN BEARING – ASSEMBLY
• Scale: 1:1
• Projection Symbol: First Angle Projection symbol (truncated cone symbol) drawn in the title block.
• Material Notes: Body – C.I., Bush – G.M.

Key Drawing Conventions:

• Section lines (hatching) at 45°, spaced 3–4 mm apart.
• C.I. hatching: thin lines at 45°.
• G.M. hatching: cross-hatching or closer lines at 45° (differentiated from C.I.).
• Centre lines: thin chain (dash-dot) lines through the bore axis.
• Dimension lines: thin continuous lines with arrowheads.
• All fillets and rounds = R5 (shown as small arcs at corners in section).

Given Information:

• Assembly given: Open Bearing (Fig. 3.7)
• Task: Disassemble and draw detail (part) drawings of Base and Bush separately.
• Scale: 1:1
• Projection: First Angle

Step 1 – Identify Parts from Assembly

From the Open Bearing assembly:

• Base (Body) – C.I.: Rectangular pedestal with a semi-circular open recess at the top to seat the bush. Has a flat base with bolt holes.
• Bush – G.M.: Half-cylindrical bush (semi-circular cross-section) that fits into the recess of the base.

Step 2 – Part (a): BASE

(i) Front View of Base – Left Half in Section:

1. Draw the full front view outline of the Base (body) — a rectangular block with a semi-circular recess at the top centre.
2. On the LEFT half: draw the sectional view along the vertical centre plane.

• In section, show the internal profile: the semi-circular seat, the solid walls of the body, the base thickness.
• Apply C.I. hatching (45° lines, 3–4 mm spacing) to all cut surfaces.

3. On the RIGHT half: show the external view — visible edges of the body, bolt holes (as hidden or visible depending on position), outer profile.
4. Show fillets R5 at all internal corners in section.
5. Draw centre lines through the axis of the semi-circular seat.

(ii) Top View of Base:

1. Project the top view directly below the front view.
2. Show the rectangular base outline.
3. Show the semi-circular recess (open at top) as a visible semi-circle at the centre.
4. Show bolt holes as circles at the four corners (or as per given drawing).
5. Show centre lines.
6. Hidden edges (e.g., underside features) shown as dashed lines.

Six Important Dimensions for Base:
$$\text{1. Overall length} = 100 \text{ mm}$$
$$\text{2. Overall width} = 60 \text{ mm}$$
$$\text{3. Height of body} = 60 \text{ mm}$$
$$\text{4. Diameter of semi-circular seat} = \phi\,50 \text{ mm}$$
$$\text{5. Bolt hole diameter} = \phi\,10 \text{ mm}$$
$$\text{6. Base plate thickness} = 15 \text{ mm (or as given)}$$

Step 3 – Part (b): BUSH

(i) Front View of Bush – Right Half in Section:

1. Draw the full front view outline of the Bush — a half-cylinder (flat face at bottom, curved face at top).
2. On the RIGHT half: draw the sectional view along the vertical centre plane.

• In section, show the inner bore (hollow semi-circle) and the wall thickness of the bush.
• Apply G.M. hatching (cross-hatching or differentiated 45° lines) to cut surfaces.

3. On the LEFT half: show the external view — the curved outer surface and flat bottom face.
4. Draw centre lines through the bore axis.

(ii) Top View of Bush:

1. Project the top view below the front view of the bush.
2. Show the rectangular outline of the bush (length × width of the half-cylinder).
3. Show the inner bore as a rectangle (or semi-circle depending on orientation) with hidden/visible lines.
4. Show centre lines.

Six Important Dimensions for Bush:
$$\text{1. Outer diameter of bush} = \phi\,50 \text{ mm}$$
$$\text{2. Inner bore diameter} = \phi\,25 \text{ mm}$$
$$\text{3. Length of bush} = 60 \text{ mm (or as given)}$$
$$\text{4. Wall thickness} = \frac{50-25}{2} = 12.5 \text{ mm}$$
$$\text{5. Overall height of bush (semi-circle)} = 25 \text{ mm (radius)}$$
$$\text{6. Width of flat face} = 50 \text{ mm}$$

Step 4 – Title Block and Projection Symbol

• Title (a): BASE – OPEN BEARING, Scale 1:1, Material: C.I.
• Title (b): BUSH – OPEN BEARING, Scale 1:1, Material: G.M.
• Projection Symbol: First Angle Projection symbol in title block of each sheet.

Key Conventions:

• Sectioned surfaces hatched at 45°; C.I. and G.M. hatching differentiated.
• Centre lines as thin chain lines.
• All fillets R5 shown in section views.
• Dimension lines thin with arrowheads; all dimensions in mm.

Given: Detail (part) drawings of a Sleeve and Cotter Joint. All rounds and fillets = R4. Scale 1:1.

Concept: A Sleeve and Cotter Joint connects two co-axial rods end-to-end. The sleeve is a hollow cylinder that fits over the spigot ends of both rods; cotters are driven through transverse slots to lock the assembly.

Step-by-step procedure for Assembly Drawing:

Step 1 – Identify the parts from the detail drawings:

• Two rods (Rod A and Rod B) with spigot ends having cotter slots.
• One sleeve (hollow cylinder) with two cotter slots.
• Two cotters (tapered flat wedges).

Step 2 – Establish the principal axis:
Place the common axis of the rods and sleeve horizontal, parallel to V.P. (so the front view shows the full length).

Step 3 – Draw the Front View (lower half in section):

1. Draw the centre line (horizontal axis) of the assembly.
2. Draw the outer profile of the sleeve (rectangle representing the outer cylinder) symmetrically about the axis.
3. For the lower half in section: the lower half is cut by a horizontal cutting plane passing through the axis.

• Show the cross-hatching (section lines at 45°) on the cut surfaces of the sleeve and the rod spigot ends.
• The upper half remains as an external (outside) view showing hidden lines where necessary.

4. Show the two rods entering the sleeve from both ends; their spigot ends are visible inside the sleeve in the sectioned lower half.
5. Show the two cotters in their respective slots — cotters appear as rectangles in the front view; apply section lines to the cotter cross-sections.
6. Show taper of cotters (typically 1:30 or as given in detail drawing).
7. Mark all rounds and fillets as R4.
8. Add centre lines, dimension lines, and 6 important dimensions (e.g., rod diameter $\phi d$, sleeve outer diameter $\phi D$, sleeve length $L$, cotter width $w$, cotter thickness $t$, slot width).

Step 4 – Draw the Left Side View:

1. Project from the front view to the right (left side view is placed to the right of the front view in first-angle projection).
2. The left side view shows the end face of the sleeve as a circle (outer diameter $D$) with a concentric circle (inner diameter = rod diameter $d$).
3. The cotter slot appears as a rectangle across the circular face.
4. Show the rod end as a circle of diameter $d$ inside the sleeve bore.
5. Add centre lines.

Step 5 – Finishing:

• Write title block: SLEEVE AND COTTER JOINT.
• Write scale: 1:1.
• Draw the first-angle projection symbol.
• Give 6 important dimensions.

Key dimensions to mark (typical for standard sleeve and cotter joint):
$$d = \text{rod diameter},\quad D = 2d,\quad L_{\text{sleeve}} = 8d,\quad \text{cotter taper} = 1:30,\quad w_{\text{cotter}} = 1.5d,\quad t_{\text{cotter}} = 0.4d$$

Result: The assembled front view (lower half in section) and left side view are drawn to scale 1:1 as per first-angle projection.

Given:

• A Turnbuckle consisting of: Body (M.S.) – 1 off, Rod A (M.S.) – 1 off, Rod B (M.S.) – 1 off.
• Scale: 1:1
• 55 mm threaded portion of each rod is inserted inside the body.

Concept / Assembly Principle:
A Turnbuckle is a tie-rod joint used to connect two rods under tension. The body is a hexagonal or cylindrical barrel with internal right-hand (RH) thread at one end and left-hand (LH) thread at the other end. Rod A has RH external thread and Rod B has LH external thread. When the body is rotated, both rods are drawn in or pushed out simultaneously.

Steps for Drawing:

Step 1 – Understand the parts:

• Body: Hexagonal barrel with a central hole threaded RH on one side and LH on the other. Note the overall length and outer hexagonal size from the given detail drawing.
• Rod A: Cylindrical rod with RH threaded end (thread length sufficient to insert 55 mm inside body).
• Rod B: Cylindrical rod with LH threaded end (thread length sufficient to insert 55 mm inside body).

Step 2 – Assembly:

• Screw Rod A into the RH threaded end of the body so that 55 mm of its threaded portion lies inside the body.
• Screw Rod B into the LH threaded end of the body so that 55 mm of its threaded portion lies inside the body.
• The two rods project outward from either end of the body.

Step 3 – Draw Front View (Upper Half in Section):

• Draw the overall outline of the assembled turnbuckle as a front view.
• The upper half is shown in section (cutting plane passes through the axis).
• In the sectioned upper half:
• Show the internal threads of the body (represented by thin lines for thread roots and thick lines for thread crests, or by conventional thread representation as per SP:46).
• Show 55 mm of Rod A's threaded shank inside the body on the RH side.
• Show 55 mm of Rod B's threaded shank inside the body on the LH side.
• Apply hatching (section lines at 45°) to the cut surfaces of the body.
• The lower half shows the external hexagonal profile of the body and the external view of the rods.
• Mark the 55 mm insertion depth with a dimension line on each side.

Step 4 – Draw Left Hand Side View:

• Project the left-hand side view from the front view.
• The body appears as a regular hexagon (across flats dimension as given).
• The rod appears as a circle (diameter of rod shank) concentric with the hexagon.
• Show hidden lines if required for the internal bore.

Step 5 – Dimensioning and Labelling:

• Provide overall length of assembly.
• Diameter of rods.
• Across-flats dimension of body.
• Length of body.
• 55 mm threaded insertion length.
• Thread designation (e.g., M20 or as per given detail).
• Write title: TURNBUCKLE — ASSEMBLY, Scale 1:1.

Important Note on dimensions (read from detail drawing Fig. 5.8):

• Overall length of body ≈ as given in detail.
• Rod diameter and thread size as given.
• The total assembled length = Length of body + protruding length of Rod A + protruding length of Rod B (after 55 mm insertion each side).

Result: The assembled front view (upper half in section) clearly shows the internal threaded engagement of 55 mm on each side, and the left-hand side view shows the hexagonal cross-section of the body with the rod circle inside.

Given: Detail (part) drawings of an Unprotected Flange Coupling as shown in Fig. 6.8.

Scale: 1:1 (Full Size)

Parts Identified in an Unprotected Flange Coupling:

1. Flange A (with hub, flange disc, bolt holes, keyway)
2. Flange B (with hub, flange disc, bolt holes, spigot/socket recess, keyway)
3. Shaft A
4. Shaft B
5. Key A (Rectangular Sunk Key)
6. Key B (Rectangular Sunk Key)
7. Bolts, Nuts and Washers (typically 3 or 4 sets)

Assembly Procedure (Step-by-Step):

Step 1 – Understand the assembly:

• The two shafts (Shaft A and Shaft B) are to be coupled end-to-end.
• Flange A is fitted on Shaft A using Key A; Flange B is fitted on Shaft B using Key B.
• The two flanges are brought face-to-face; the spigot of one flange fits into the socket (recess) of the other for alignment.
• Bolts pass through the bolt holes in both flanges and are secured with nuts and washers.

Step 2 – Draw the Front View (Upper Half in Section):

• Draw the horizontal axis (shaft centre line) as a chain-dot line.
• Draw the two shafts as rectangles (diameter as given, e.g., $\phi 40$ mm) extending from both sides.
• Draw the hubs of Flange A and Flange B around the respective shafts.
• Show the keyways on the shafts and in the hubs in the sectional half.
• Draw the flange discs of both flanges meeting at the centre.
• Show the spigot (projection) of one flange fitting into the socket (recess) of the other.
• In the upper half (above the centre line): draw the section — apply hatching (thin lines at $45°$) to all cut solid parts (hub, flange disc, shaft cross-section). Bolts passing through bolt holes are not hatched (bolts are not sectioned by convention).
• In the lower half (below the centre line): draw the external (outside) view — show the bolt heads/nuts, the outer profile of flanges and hubs.
• Show all important dimensions: shaft diameter, hub diameter, hub length, flange diameter, flange thickness, bolt circle diameter (PCD), bolt diameter, number of bolts, overall length, keyway dimensions.

Step 3 – Draw the Right Hand Side View (Without Section):

• Project from the front view to the right.
• This view shows the right-side face of Flange B (or Flange A depending on orientation).
• Draw the outer circle of the flange disc.
• Draw the bolt holes (as circles) equally spaced on the pitch circle diameter (PCD).
• Draw the hub circle (concentric).
• Draw the shaft circle (innermost concentric circle).
• Show the nuts (hexagonal or square) on the bolt ends if visible.
• Show centre lines for all circles.
• No hatching (no section in this view).

Step 4 – Dimensioning:

• Dimension all diameters with the $\phi$ symbol: shaft $\phi$, hub outer $\phi$, flange outer $\phi$, bolt circle $\phi$, bolt hole $\phi$.
• Dimension lengths: hub length, flange thickness, overall coupling length.
• Dimension keyway: width $\times$ depth.
• Use leader lines and dimension lines as per SP:46 conventions.

Step 5 – Title Block and Projection Symbol:

• Write Title: ASSEMBLY OF UNPROTECTED FLANGE COUPLING
• Write Scale: 1:1
• Draw the First Angle Projection Symbol (frustum of cone — as used in CBSE/Indian standard) in the title block.

Key Conventions to Follow:

• Centre lines: thin chain-dot lines.
• Cutting plane line shown on the front view.
• Section lines (hatching) at $45°$, equally spaced ($\approx 3$ mm apart).
• Bolts, keys, shafts — not sectioned even if the cutting plane passes through them.
• Hidden lines may be omitted in the sectional view for clarity.

Result: The assembled orthographic views of the Unprotected Flange Coupling are drawn to scale 1:1 with the front view (upper half in section) and the right-hand side view (without section), fully dimensioned with title and projection symbol.

Given: Detail (part) drawings of a Solid Cast-Iron (C.I.) Pulley are provided. The parts are: (i) Pulley body (solid web/disc type), (ii) Shaft, and (iii) Key.

Concept: An assembly drawing combines all individual parts in their correct working positions. A half-sectional front view shows the lower half cut by a horizontal cutting plane passing through the axis, revealing internal features (hub bore, keyway, web thickness, rim profile), while the upper half remains as an external view.

Step-by-Step Procedure:

Step 1 – Identify the parts and their dimensions (read from the given detail drawings):

• Pulley: overall diameter (D), face width (B), rim thickness, hub diameter, hub length, bore diameter, keyway dimensions.
• Shaft: diameter equal to bore of pulley hub.
• Sunk Key: width × height × length as per keyway.

Step 2 – Establish the position w.r.t. H.P. and V.P.:

• The pulley axis is kept horizontal (parallel to V.P. and perpendicular to H.P. in the standard position).
• The shaft passes through the hub bore along the pulley axis.
• The key is fitted in the keyway between shaft and hub.

Step 3 – Draw the Front View (lower half in section), Scale 1:1:

1. Draw the centre lines — one horizontal (axis of pulley/shaft) and one vertical (centre of face width).
2. Upper half (external view):

• Draw the outer rim profile: two horizontal lines at $\pm D/2$ from axis, connected by the face-width lines.
• Show the crowned (slightly convex) or flat rim face.
• Show the hub as a cylinder of hub-diameter and hub-length, projecting symmetrically about the web.
• Show the solid web (disc) connecting rim to hub.

3. Lower half (sectional view — cut by horizontal plane through axis):

• Show the cross-section of the rim (rectangular section of thickness $t_r$).
• Show the solid web in section (hatched with cast-iron hatching — thin lines at 45°).
• Show the hub cross-section: outer hub diameter and inner bore diameter; keyway slot visible at the top of the bore.
• Show the shaft (circle/rectangle in section) inside the bore — shaft is NOT hatched (standard practice: shaft not cut in section).
• Show the key in section (hatched) sitting in the keyway.

4. Draw the cutting-plane line (chain line with arrows) along the horizontal axis in the side view to indicate the section.

Step 4 – Draw the Left Side View, Scale 1:1:

1. Project from the front view.
2. Draw concentric circles:

• Outermost circle: rim outer diameter $D$.
• Next circle: rim inner diameter $(D - 2t_r)$.
• Hub outer circle: hub diameter $d_h$.
• Bore circle: bore diameter $d_b$ (= shaft diameter).

3. Show the solid web as the area between hub and rim (no spokes — solid disc).
4. Show the keyway as a small rectangular slot at the top of the bore circle.
5. Show the shaft ends projecting beyond the hub on both sides (visible as circles coinciding with bore).
6. Apply centre lines.

Step 5 – Dimensioning (6 important dimensions):

$$\boxed{\text{1. Overall diameter of pulley } (D)}$$
$$\boxed{\text{2. Face width of pulley } (B)}$$
$$\boxed{\text{3. Bore diameter / Shaft diameter } (d)}$$
$$\boxed{\text{4. Hub diameter } (d_h) \text{ and Hub length } (L_h)}$$
$$\boxed{\text{5. Rim thickness } (t_r)}$$
$$\boxed{\text{6. Key dimensions: Width} \times \text{Height} \times \text{Length}}$$

Step 6 – Title Block and Projection Symbol:

• Write title: SOLID C.I. PULLEY — ASSEMBLY DRAWING
• Scale: 1:1
• Draw the First-Angle Projection symbol (frustum of cone symbol) in the title block.

Key Drawing Notes (Board Exam Tips):

• In the sectional front view, hatch the pulley body (rim, web, hub) with thin lines at 45° (C.I. hatching — single direction, equally spaced).
• The shaft is not hatched even though it appears in the section (standard rule: shafts, keys, bolts are not sectioned when cut longitudinally).
• The key IS hatched (it is cut transversely/across its length in the front view section).
• The boundary between the sectioned lower half and the unsectioned upper half is shown by a horizontal centre line (no extra line needed if the cutting plane coincides with the axis).
• The left side view is placed to the right of the front view in First-Angle Projection.

Final Answer: The assembled views — (a) Front view with lower half in section and (b) Left side view — are drawn at Scale 1:1 in First-Angle Projection with 6 dimensions and title block as described above (refer to Fig. 7.8 of the textbook for the finished drawing).