CNC Machining Tolerances

±0.005″ is the standard tolerance for production machined parts at Velocity CNC. This applies to features where the drawing callout does not specify tighter — and it is held through production, not just at first article. The first article inspection documents every dimension to the drawing; production inspection targets the critical dimensions with CMM verification.

0.0001″ is achievable on qualifying geometry. "Qualifying geometry" means features where the form, fixturing approach, and tool access allow the process to hold the tighter specification repeatably — not features where holding 0.0001″ requires a 90% rejection rate to find the conforming parts. If your drawing specifies 0.0001″ on a feature that our drawing review identifies as a process risk, we say so before the quote is issued.

Material Effects on Achievable Tolerance

Titanium and Inconel are less forgiving than aluminum at tight tolerances. Thermal expansion during machining, work hardening in Inconel, and residual stress in billet titanium all affect dimensional stability. The tolerance achievable on a Ti-6Al-4V bore is not the same as the tolerance achievable on the same bore geometry in 7075-T6. Our drawing review addresses this directly — material-specific process strategy is part of how we quote tight-tolerance work across aerospace and automotive programs.

CMM Verification and Documentation

Critical dimensions are verified by CMM on every qualifying part and documented in the dimensional inspection report. The CMM program is developed from your drawing and executed on the actual production part — not estimated or extrapolated from similar geometry. The inspection report traces each measured dimension to the drawing callout and records the actual measured value. This is the documentation your receiving inspection team needs to complete their inspection without calling us.