Tolerance stackup analysis of a simple part

This article takes you through a simple example of how tolerance stack up analysis is carried out to find unknown dimensions and gaps

Consider a component as shown with dimensions and tolerances given .

How can we find the specification in red?

Generic process for Worst case tolerance stack up analysis

  1. Label the distance to be studied A-B
  2. Positive and negative directions are set
    1. Left to Right is positive
    2. Right to left is negative
  3. Develop loop diagram starting from A to B
  4. Start from A and move towards B through Loop
  5. The dimensions in positive direction are added together and dimensions in negative are added together
  6. Negative dimensions sum is subtracted from positive direction sum .
  7. All tolerances are added with each other . The total added tolerance is possible allowed variation for distance being studied

Loop Diagram with the tolerance analysis table:

For a full course on Tolerance stackup analysis with and without GD&T 

have a look here : Basics of Tolerance analyses : Stackups and Fits

Categories: : GD & Tolerancing