The drawing of the cotter joint with socket and spigot ends involves several steps to accurately represent its components and their assembly. The rods are 30 mm in diameter.

1. Spigot End Drawing:
   Draw the main rod of 30 mm diameter. At one end, create a spigot by reducing the diameter and extending it. The spigot typically has a tapered end for the cotter. Detail the dimensions for the spigot length, diameter, and taper angle (usually 1 in 30).
2. Socket End Drawing:
   Draw the second rod of 30 mm diameter. At one end, create a socket by forming a hollowed-out section that will receive the spigot. This socket is usually bored out to accommodate the spigot and has a split or two halves to grip the spigot firmly when the cotter is inserted. Detail the dimensions for the socket length and bore diameter.
3. Cotter Drawing:
   Draw the cotter separately. The cotter is a tapered flat bar. Its dimensions are critical: its width should be slightly less than the diameter of the rod, its thickness should be sufficient to provide strength, and its taper (usually 1 in 30) matches the taper on the spigot and the slot in the socket.
4. Assembly - Front View (Half Sectional):
   Assemble the spigot and socket ends. For the front view, show the top half in section and the bottom half in full view. This means the top half of the spigot, socket, and the cotter will be sectioned to reveal internal details. The bottom half shows the external profile. The cotter is shown passing through the slot in the socket and the tapered end of the spigot.
5. Assembly - Side View:
   Draw the side view of the assembled joint. This view typically shows the full outline of the components without sectioning, unless specific side details need to be revealed. It helps to visualize the overall length and alignment of the rods and the cotter.
6. Dimensioning:
   Add all necessary dimensions to the drawing, including rod diameters, spigot and socket dimensions, cotter dimensions, and lengths of engagement. Ensure all dimensions are clear and follow standard engineering drawing practices.
7. Labeling:
   Label the different parts of the joint (e.g., Spigot, Socket, Cotter, Rod).

The sectional view is crucial for understanding how the cotter fits into the tapered slots of the spigot and socket, and how it secures the joint. The half-section is used to save drawing time and complexity while still providing complete information about the internal structure.

A universal coupling (Hooke's joint) connects two shafts whose axes intersect at a small angle. For shafts of diameter d = 30 mm, the standard proportions are as follows:

• Fork end diameter (D) = 2d = 60 mm
• Pin diameter (d1) = 0.6d = 18 mm
• Central block (cross) diameter = 2d = 60 mm
• Fork thickness = 0.5d = 15 mm
• Pin length = 3d = 90 mm

The sectional front view is drawn by taking a vertical section through the center of the cross-pin. The two shafts are shown connected to the forks, which are bolted or keyed to the shaft ends. The central cross-piece is shown in section, connecting the two forks at right angles to each other. The side view is projected from the front view, showing the circular profile of the shaft and the arrangement of the fork ends and the cross-pin head.

Key drawing considerations include:

1. Draw the center lines for both shafts intersecting at the desired angle.
2. Construct the forks with the calculated proportions, ensuring the clearance for the cross-piece.
3. Represent the cross-pin clearly, showing its head and the split pin or nut fastening arrangement.
4. Apply standard section lining (hatching) to the forks and the cross-piece in the front view to distinguish the components.
5. Label the assembly and indicate the primary dimensions (d=30 mm) to verify the scale of the drawing.