Hand taps nomenclature: A tap having its end tapered for about 3–4 threads (used after a taper tap and before bottoming) is called a

Difficulty: Easy

Correct Answer: second (plug) tap

Explanation:


Introduction / Context:
Hand tapping sets usually include three taps: taper, second (plug), and bottoming. They differ in the amount of chamfered (tapered) threads at the nose, which determines ease of starting and ability to cut close to the hole bottom.


Given Data / Assumptions:

  • Standard metric/imperial hand tap set.
  • Threading a blind or through hole progressively.
  • Typical chamfer thread counts: taper ≈ 8–10, second ≈ 3–5, bottoming ≈ 1–1.5.


Concept / Approach:
A 3–4 thread chamfer corresponds to the intermediate or “second/plug” tap. It follows the taper tap (easy starting) and precedes the bottoming tap (finishing to full depth near blind hole bottoms).


Step-by-Step Solution:

Relate stated 3–4 thread chamfer to standard tap types.Map: 8–10 → taper; 3–5 → second/plug; 1–1.5 → bottoming.Therefore answer = second (plug) tap.


Verification / Alternative check:
Tool catalogs confirm the chamfer ranges and usage order for hand sets.


Why Other Options Are Wrong:

  • Taper tap has longer chamfer (8–10) for starting only.
  • Bottoming has almost no chamfer; used to finish near the bottom.
  • Spiral point taps are machine taps with different geometry, not defined by 3–4 chamfer threads in hand set context.


Common Pitfalls:
Confusing plug/second with bottoming; remember bottoming has the shortest chamfer to reach full depth.


Final Answer:
second (plug) tap

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