CNC Machining Tolerances: The Complete Guide (2025)
A practical reference for mechanical engineers: typical tolerances, drivers, and design trade-offs.
Typical Tolerances
- General machining: ±0.005 in (0.13 mm)
- Reamed holes: ±0.001 in (0.025 mm)
- Flatness/parallelism: per part size
What Drives Tolerances
- Material (Al vs SS vs Ti)
- Tool reach and rigidity
- Workholding, thermal effects, finish