Machine capacity terminology: A “15 mm drilling machine” can drill a hole of what capacity?
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AMaximum diameter 15 mm
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BIn 15 mm thick plates only
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CCross-sectional area 15 mm^2
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DNone of these
Answer
Correct Answer: Maximum diameter 15 mm
Explanation
Introduction / Context:Manufacturers describe drill presses by a capacity number (e.g., 10 mm, 15 mm, 25 mm). Understanding this nomenclature helps select the correct machine for a job.
Given Data / Assumptions:
- Capacity refers to mild steel drilling capability under standard conditions.
- Tooling and feeds are appropriate for the rating.
Concept / Approach:The capacity designation indicates the largest hole diameter the machine is designed to drill in a typical material (commonly mild steel) with standard tooling, within safe power and rigidity limits.
Step-by-Step Solution:
Identify what capacity generally means in specs.Translate “15 mm machine” → drills up to 15 mm diameter.Plate thickness or area figures are not part of capacity naming.Therefore, correct interpretation is maximum diameter 15 mm.Verification / Alternative check:Spec sheets show motor power, spindle taper, and “maximum drilling diameter” matching the capacity value.
Why Other Options Are Wrong:
- “In 15 mm thick plates” confuses thickness with diameter capacity.
- “15 mm^2 area” is unrelated to drilling capacity terminology.
- “None of these” is incorrect since the standard meaning is well defined.
Common Pitfalls:Ignoring that real achievable diameter depends on work material; hard alloys may require derating even if the nominal capacity is 15 mm.
Final Answer:Maximum diameter 15 mm