🔍 Key Concepts

• American Standard (Unified) V‑thread geometry • Difference between the included thread angle and the half-angle to the centerline • How angle L is shown in the illustration relative to the screw axis

💭 Think About

• Look closely at where the arrow for angle L is drawn. Is it measuring the full V at the crest/root, or just one flank relative to the centerline? • Recall the standard V‑shape used on common machine screws and bolts. What is the total angle between the two flanks, and what would that make the angle from one flank to the centerline? • Compare each choice to what you know about typical sharp V‑threads versus square or Acme threads. Which of these angles is characteristic of the common American Standard V‑thread form?

✅ Before You Answer

• Verify whether L is the angle between one side of the thread and the axis, or the full V between both flanks. • Recall the standard included angle for American (Unified) screw threads from basic machine shop or engineering data. • Eliminate options that match angles typical of Acme (29°) or square threads, since those are not American Standard V‑threads.