Depth of thread varies from type to type. From the following, choose the thread with maximum depth 

Explanation:

Depth of Threads:

• Different types of threads have varying depths based on their profiles and applications.

Square Thread:

• Square threads have a square cross-section and are used for high power transmission with minimal friction.
• Depth: \(\text{Depth} = \frac{P}{2}\) where \(P\) is the pitch.

Acme Thread:

• Acme threads have a trapezoidal profile and are easier to manufacture than square threads.
• Commonly used in lead screws for lathes, brass valves, and vices.
• Depth: \(\text{Depth} = \frac{P}{2} + 0.01\) where \(P\) is the pitch.

Worm Thread:

• Worm threads are used in worm gears and have a helical profile.
• Designed for proper meshing with the worm wheel.
• Depth: \(\text{Depth} = 0.68 \times P\) where \(P\) is the pitch.

Buttress Thread:

• Buttress threads are used for high axial thrust applications, such as in vices and jacks.
• They combine the efficiency of square threads and the strength of V-threads.
• Depth: \(\text{Depth} = 0.75 \times P\) where \(P\) is the pitch.

Comparison of Thread Depths:

• Square Thread: Proportional to \(\frac{P}{2}\)
• Acme Thread: Slightly greater than \(\frac{P}{2}\)
• Worm Thread: Proportional to \(0.68 \times P\)
• Buttress Thread: Proportional to \(0.75 \times P\)

Conclusion:

The Buttress Thread has the maximum depth relative to the pitch.