Why do perfectly “in-tolerance” parts sometimes fail to assemble?
Tolerance stack-up is the accumulation of variation from individual part tolerances in an assembly. Even if each part meets its drawing limits, the combination can lead to:
- Interference (too tight)
- Excessive gap (too loose)
This happens because tolerances add together along a dimension chain.
Key takeaway:
✔ Good parts ≠ Good assembly
✔ You must analyze the full chain, not individual parts
Leave a Reply