Precision Machining
Precision machining produces components to tight tolerances, typically ±0.005–0.01 mm on critical dimensions, with controlled geometry such as roundness, flatness and position. It combines stable CNC machines, suitable tooling and careful inspection for mating fits and high-performance assemblies.
What it is
Precision work depends on the whole process: a stable machine, the right fixturing, temperature control, tool wear management and in-process measurement. Very tight features are often finished by grinding, honing or lapping after machining.
Geometric tolerances (GD&T) such as concentricity, perpendicularity and true position are verified with instruments like micrometers, bore gauges, height gauges and CMM where required.
Typical applications
- Bearing seats and precision fits
- Hydraulic valve spools and bodies
- Instrument and measuring equipment parts
- Aerospace, medical and defence-style parts
- Tooling, gauges and fixtures
Suitable materials
- Alloy and tool steels
- Stainless steel
- Aluminium alloys
- Bronze and brass
- High-performance plastics (PEEK, POM)
Points to consider
- Apply tight tolerances only where the function needs them; each tight feature adds machining and inspection time.
- Use ISO fit designations (for example H7/g6) to communicate fits clearly.
- Thin walls and long slender parts are hard to hold to tight tolerances; allow for stress relief or grinding.
- State which dimensions need inspection reports (first article, CMM) at the quote stage.
Frequently asked questions
What tolerance counts as precision machining?
Generally ±0.01 mm or tighter on critical features, together with geometric controls such as roundness or position. Anything beyond about ±0.005 mm usually involves grinding or lapping.
Can you provide inspection reports?
Yes. Dimensional inspection reports, first-article reports and CMM reports can be arranged when specified at the quote stage.
How do I specify a precision fit?
Use ISO fit codes such as H7 for the hole and g6 or k6 for the shaft. Our ISO fits chart in the Resources section lists common combinations.