Tolerances & Fits in Engineering Drawings Flashcards

A dimension shown as 62.50/62.45 on a drawing uses which tolerance expression method?

Answer: Limit dimensioning

Limit dimensioning directly states the maximum and minimum acceptable sizes without referencing a nominal value or deviation.

If a shaft has a tolerance of 0.025 mm and the mating hole has a tolerance of 0.030 mm, what is the assembly tolerance?

Answer: 0.055 mm

Assembly tolerance equals the sum of both component tolerances: 0.025 + 0.030 = 0.055 mm.

In the shaft-basis fit system, which letter designates the reference shaft with zero fundamental deviation?

Answer: h

In the shaft-basis system, 'h' designates the reference shaft whose upper deviation is zero.

Which statement correctly describes 'least material condition' (LMC) for an external feature (shaft)?

Answer: The shaft is at minimum diameter

LMC for an external feature (shaft) occurs at its smallest permissible diameter, where the least material is present.

A clearance fit specified as H8/f7 compared to H7/f6 would generally have:

Answer: Larger tolerances and more clearance variation

Higher IT grade numbers (8 vs 7, 7 vs 6) mean wider tolerance zones, resulting in more variation in clearance across the assembly.

A tolerance accumulation problem in a stack-up occurs when:

Answer: Individual tolerances of multiple parts combine to produce excessive assembly variation

Tolerance stack-up occurs when multiple independent tolerances add together in a chain, potentially causing parts to not assemble correctly.

According to ASME Y14.5, unless otherwise specified, general tolerances on drawings apply to:

Answer: All directly toleranced dimensions without specific tolerances

General tolerances (title block tolerances) apply to all dimensions that do not carry their own specific tolerance callout.