MODULE 1-3 Flashcards
(12 cards)
stated permissible variation of the size of a dimension
TOLERANCE
size of the part is permitted to be either larger or smaller than the given dimension
BILATERAL
-size of the part maybe larger only, or smaller only than the given dimension.
-generally used on those dimensions involved in fit such as a pin in a hole
UNILATERAL
difference between the dimensions of the two mating parts of the difference between the smallest hole and largest shaft.
ALLOWANCE
if the dimension of the pin is larger that of the hole, also called the interference of metal
NEGATIVE ALLOWANCE
defined as the degree of tightness or looseness between two mating parts
FITS
positive difference between the size of the hole and the shaft allowing relative movement between them
CLEARANCE FITS/ RUNNING FITS/ SLIDING FITS
allowances and tolerances are a practical necessity when many mating parts are be produced.
INTERCHANGEABILITY
hole is smaller than the shaft it will take force or pressure to put the cold parts together. The tolerance is said to be negative and is termed the interference of metal
PRESS AND SHRINK FITS
relative finely spaced irregularities of the surface
ROUGNESS
irregularities of departure from the nominal surface of the greater spacing than roughness
WAVINESS
direction of the predominant surface pattern
LAY
