Jigs vs. fixtures vs. gauges: primary purpose of a jig In production tooling, what is the main function of a jig?
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ATo hold the work and also guide the cutting tool in drilling, reaming, or tapping
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BTo hold and support the work during milling, grinding, planing, or turning (fixture)
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CTo inspect and verify the accuracy of the manufactured part (gauge)
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DNone of the above
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ETo supply cutting fluid to the tool-work interface
Answer
Correct Answer: To hold the work and also guide the cutting tool in drilling, reaming, or tapping
Explanation
Introduction / Context:Production tooling uses jigs, fixtures, and gauges to improve accuracy, speed, and interchangeability. Each has a distinct role in the manufacturing system.
Given Data / Assumptions:
- Common hole-making operations (drilling, reaming, tapping).
- Need for repeatable tool location without extensive layout/marking.
Concept / Approach:A jig locates and holds the workpiece and additionally guides the tool (via drill bushings), ensuring precise hole location. A fixture locates and holds but does not guide the tool; it is used for processes like milling or turning. A gauge checks dimensions/geometry after processing.
Step-by-Step Solution:Identify the need to guide the tool → select jig.If only holding/supporting the work → fixture.For inspection → gauge.
Verification / Alternative check:Standard manufacturing texts define jigs by their tool-guiding function through hardened bushings.
Why Other Options Are Wrong:
- (B) describes fixtures (no tool guidance).
- (C) describes gauges, not jigs.
- (E) is a coolant delivery system function, unrelated to jigs.
Common Pitfalls:Using “jig” and “fixture” interchangeably; omitting bushings leading to rapid wear in guide holes.
Final Answer:To hold the work and also guide the cutting tool in drilling, reaming, or tapping