If p is the pitch, d is the nominal diameter and d’ is the bolt hole diameter, then the minimum pitch is
- A3 d
- B3 d’
- C2.5 dCorrect
- D2.5 d’
Solution
Concept
Spacing of bolts (IS 800)
Formula
p ≥ 2.5 d
Step-by-step solution
1. Minimum pitch = 2.5 × nominal diameter of the bolt.
Explanation
The pitch must be large enough to avoid hole interaction.
Why the other options are wrong
3d and 3d′ are not the minimum; 2.5d′ uses the hole diameter.
Shortcut
Pitch ≥ 2.5d; edge ≥ 1.5d′.
Common mistake
Using 3d.
Correct answer: C) 2.5 d