Riveted joints – hole oversize: For rivet diameters over 25 mm, by how much is the rivet hole diameter typically made larger than the nominal rivet diameter to allow for insertion and driving?

Introduction / Context:
In riveted construction (and analogously for some bolted work), holes are made slightly larger than the fastener to account for fabrication tolerances and ease of installation. The recommended oversize depends on the fastener diameter.

Given Data / Assumptions:

• Traditional hot-driven rivets in structural steel.
• We focus on rivet diameters > 25 mm.
• Looking for the standard oversize value used in shop drawings and inspection.

Concept / Approach:

Common practice sets the hole oversize to about 1.5 mm for rivet diameters up to and including 25 mm; for larger rivets (over 25 mm) the oversize is typically 2.0 mm. This maintains adequate net section while ensuring practical driving and proper fit-up under field conditions.

Step-by-Step Solution:

Verification / Alternative check:

Tabulated values in traditional steel design texts and specifications list +1.5 mm for ≤25 mm and +2.0 mm for >25 mm rivets, balancing fit-up and net-section loss considerations.

Why Other Options Are Wrong:

• 1.0–1.5 mm: used for smaller rivets; insufficient for large diameters.
• 2.5–3.0 mm: overly large, causing unnecessary reduction in net area and potential alignment issues.

Common Pitfalls:

• Using a single oversize value for all diameters without checking the transition at 25 mm.
• Failing to account for net-section reduction in tension members due to holes.

Final Answer:

2.0 mm.