Essay · Level 5 · 222 words

Allowable Error

Original passage © Studio AM, written for Fluency.

In a machine shop, tolerance is not a virtue but a number. A drawing never asks for a shaft one inch wide; it asks for one inch plus or minus two thousandths, and that plus-or-minus records a decision about how wrong the part is allowed to be.

The decision costs money in both directions. Tighten the number and the price climbs steeply: finer tolerances demand better machines, slower cuts, more careful measurement, and a taller pile of rejected parts. Loosen it too far and the parts stop working together. An engineer who marks every dimension tight has not been careful; he has declined to think, and shipped that refusal to the shop floor as cost.

The skill, then, is not exactness but the placement of exactness. On a good drawing the tolerances map the part's duties: tight where a bearing rides, loose where nothing touches anything. Read this way, a drawing is a theory of what matters, written in thousandths of an inch.

Most crafts run the same arithmetic and hide it. A cabinetmaker leaves the back panel rough because no one will see it, and this is allocation, not laziness. Perfection applied evenly everywhere is indistinguishable from not knowing where the work matters. The mark of a master is not the absence of error. It is where the error was put.

Comprehension questions

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4 questions
1. Which statement best captures the essay's central claim?

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B. Skilled work lies in deciding where exactness matters, not in being exact everywhere.
The essay states its thesis twice, once as 'the placement of exactness' and once in the closing line: the master is known by where the error was put, not by having none.

2. Why does the essay say an engineer who marks every dimension tight 'has not been careful'?

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D. Because uniform tightness skips the real judgment of which dimensions matter, and pushes the cost of that skipped judgment onto the shop.
In the essay's terms, care means placing exactness where the part's duties demand it. Marking everything tight avoids that decision, so it looks rigorous while actually declining the work.

3. In 'this is allocation, not laziness,' allocation means:

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A. the deliberate placing of limited effort where it is needed
The rough back panel is effort deliberately withheld where it would be wasted, a choice about where effort goes, which the essay contrasts with simple laziness.

4. According to the essay, what happens when tolerances are tightened?

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C. Costs climb: better machines, slower cuts, more careful measurement, more rejected parts.
The second paragraph lists the price of tightening: better machines, slower cuts, more careful measurement, and a taller pile of rejected parts. Parts failing to fit is the cost of loosening, not tightening.

Source: Written for Fluency. Original passage © Studio AM, written for Fluency.