Grinding and polishing: design rules
Removing small amounts of material for precise dimensions and smooth surfaces.
Typical tolerance
Precision grinding typically reaches about ±0.005 mm; typical ground surface about Ra 0.2–0.8 µm.
Files to send
Drawing with tolerance, surface roughness (Ra) and the surfaces to be ground.
Common materials
Hardened steel, tool steel, stainless, ceramics, carbide.
The rules, with reasons
- Stock allowance. Leave about 0.1–0.5 mm on surfaces that will be ground. Why: Grinding is a finishing step and needs material to remove.
- Specify roughness. State the required surface roughness (Ra) on the drawing. Why: It decides the grinding and polishing steps.
- Hardened parts. Grind after heat treatment; ask about avoiding grinding burn. Why: Too much heat softens the surface.
- Thin sections. Avoid very thin walls on ground surfaces. Why: They deflect and heat up.
- Polishing grade. Name the finish (for example brushed, satin or mirror) or a sample. Why: Polish terms differ between shops.
Before you ask for a quote
- Material and hardness
- Surfaces and tolerances
- Roughness (Ra)
- Quantity
- Inspection report
Common mistakes
- No stock left for grinding
- No Ra specification
- Grinding before heat treatment
Request a quote Find manufacturers
Typical rules of thumb, not a guarantee. The manufacturer's own design guidelines override them: ask for them and check your design against both before ordering.