TOLERANCE GUIDE · 6 MIN READ
When does a ±0.02 mm tolerance make sense for CNC parts?
A tight tolerance should be applied where function requires it, not automatically across the whole drawing. Prepare a clear RFQ and request a feasibility review for the critical features.
Start with the functional dimension
Identify the dimensions that control fit, alignment, sealing, motion or an assembly interface. Mark those critical features on the drawing and explain the mating part or functional requirement where possible. General dimensions can often use a less demanding tolerance.
±0.02 mm is project-specific
For suitable part geometry, material, process and inspection requirements, partner factories can review tolerances as tight as ±0.02 mm. Feasibility is confirmed for each RFQ after reviewing the controlled drawing, critical features, quantity, material and inspection basis.
What to include in your RFQ
- 2D drawing with revision, datums and critical dimensions clearly marked
- 3D CAD model where available
- Material grade, quantity, surface finish and required inspection documentation
- Assembly context, destination and required delivery date
Ask for the inspection plan before production
Before you release an order, agree which features will be checked, the inspection method, the acceptance basis and the required report. This keeps the customer, coordinator and manufacturing partner aligned before machining begins.
Discuss a Tolerance Requirement