Tolorance notes

Why are they necessesary

• they hold precise tolorances to insure interchangeability of parts
• process of determining the amount a dim can change fromm its tolorance size

How accurate can 1/4'' be mesured

• .25
• .250
• .2500

Terms

• basic size- the exact size of a dim
• tolorance- amount dims can vary from basic size
• feature- used to identifie the geometery of the drawing being referanced
• limits of size- max and min size allowed
• allowance- limits are where the smallest clearance or largest interfearance occure, measured in MMC

Tolorance Styles

• limits dim- shows the acceptable min and max acceptable dims
• plus or minus dim/ diviation dims- show amount added and subtracted from basic sized to show acceptable dims
• symetrical dims- when + and - are equall

MMC

• max material condition
• the limit of a dim, where the max material is left on the part

LMC

• least material condition
• the limit of a dim where the least amount of material is left on the part

Types of Fit

• clearance- all dim combos produce clearance between parts
• interfearance fit- all combos of dims produce a force fit
• transitional fit- diff combos of dims, produce differant fits