Tolerances

Tolerances

• Hold precise tolerances to insure the interchangeability of parts
• Process of determining the amount a dimension can vary from its theoretical size

Basic Size

• Exact theoretical size

Tolerance

• Amount dimension can vary from basic size
• Feature used to identify the geometry of a drawing being referenced

Limits

• Maximum and minumum allowable size

Allowance

• Limits where smallest clearance or largest interference occur

Tolerance Style

• Limits dimensioning
• Plus/ minus dimensioning(deviation)
• Symmetrical Dimensioning

MMC

• Max Material Condition-limit of a dimension where the maximum material is left on the part

LMC

• Least Material Condition-limit of a dimension where the least amount of material is left on a part

Type of Fit

Clearance Fit

• All Dimension combinations will produce clearance between parts(running and sliding fit)

Interference Fit

• All combinations of dimensions will produce a force fit

Transistional Fit

• Different combination of dimensions will produce different kinds of fits