What is the purpose of tolerances in engineering drawings?

• A. To specify allowable margin of error for each dimension
• B. To increase manufacturing time
• C. To reduce costs without effect
• D. To complicate procurement

Answer: (A)

Tolerances define how much a dimension may deviate from the nominal size. They set the allowable margin of error for each dimension, so parts can still fit and function together even with natural manufacturing variation. This enables interchangeability, predictable assembly, and measurable quality, balancing precision with cost. The other options miss the purpose: tolerances aren’t about increasing manufacturing time, nor about reducing costs without effect, and they don’t deliberately complicate procurement; they provide clear criteria that help ensure parts come together reliably while controlling production costs.