Fits, Limits, and Tolerances

Basics

• This page goes over Fits, Limits, and Tolerances, and the application of them in design
• Essentially nothing is perfect, and getting something closer to perfect is costly/time intensive (see degrees of flatness / Lapping and whatnot) so you define what is acceptable for the application (ie specific hole for a shaft, etc)
• By doing this ahead of time, you take the need for "fiddling" out of the assembly / iterative design process
• Press Fit is a common example

External Links

• The Wikipedia Page on Limits and Fits
• The Wikipedia Page on Engineering Fits
• The Wikipedia Page on Engineered Tolerances
• Limits, Fits, and Tolerance Calculator (ISO System)
• A PDF by the Department of Mechanical & Aerospace Engineering at the University of Florida titled "Typical Tolerances of Manufacturing Processes"
• A Video by the YouTube Channel "Blondihacks" Titled "Fits and Tolerances, Oh My!" (Given they are a hobby machinist they give some good perspective on how various levels can be achieved in a small shop realistically, and also present it in a straightforward manner)
• A Video by the YouTube Channel "tarkka" Titled "Fits and Tolerances: How to Design Stuff that Fits Together" (Only a six minute video, so quicker to see, the others are ~20 minutes)
• A Video by the YouTube Channel "Tabletop Machine Shop" Titled "Limits and Fits: The ISO System" (Goes over the PROPER metric sytem, unlike the others shown above which use all the fraction of a thousandths of an inch mess)
• An Article by "Rapid Direct" Titled "Types of Fits: How to Choose the Right Fits in Engineering" (Has Nice Infographics, Probably will embed some)