Riveted joint patterns: in which joint does the number of rivets reduce progressively from the inner row to the outer row?

Introduction / Context:
Before widespread welding, boilers and pressure parts were joined using riveted joints with different patterns to distribute load and reduce stress concentration. Recognizing geometric patterns is a core drafting and design skill.

Given Data / Assumptions:

• Lapped or butt riveted joints in plate work.
• Comparison among chain, zig-zag, and diamond arrangements.
• Focus: relative count of rivets per row from inner to outer rows.

Concept / Approach:
In the diamond pattern, rivets are arranged so the number per row diminishes toward the edges, forming a diamond outline. This can smooth load transfer and limit edge stresses. Chain and zig-zag patterns keep a regular count of rivets per row or simply offset rivets between adjacent rows rather than tapering the number.

Step-by-Step Solution:
Identify pattern with tapered count of rivets: diamond.Eliminate chain (rows aligned) and zig-zag (staggered but constant count).Select “Diamond pattern.”

Verification / Alternative check:
Engineering drawing manuals illustrate the diamond layout with fewer rivets in the outer rows, clearly distinct from chain or zig-zag.

Why Other Options Are Wrong:
Chain: equal rivet count per row, aligned vertically.Zig-zag: staggered but non-tapered distribution.None of these: incorrect because diamond exists and fits the description.

Common Pitfalls:
Confusing “diamond” with “staggered” in general; overlooking that the defining feature is tapering of count.

Final Answer:
Diamond pattern