Surface Grinding
Surface grinding produces flat, parallel faces to tight thickness tolerances, typically ±0.005–0.01 mm, with a fine finish around Ra 0.4–0.8 µm. It is used on die plates, gauges, machine parts and hardened components after heat treatment.
What it is
The part is held on a magnetic chuck or fixture while a rotating abrasive wheel passes across it, removing a few microns per pass. Because grinding removes material so finely, it corrects distortion from hardening and achieves flatness that milling cannot.
Non-magnetic materials such as aluminium, brass or stainless are held with vacuum chucks, vices or fixtures.
Typical applications
- Die and mould plates
- Gauge blocks, parallels and jig plates
- Hardened wear strips and machine ways
- Punches, dies and cutting blades
- Precision spacers and shims
Suitable materials
- Hardened and case-hardened steels
- Alloy and tool steels
- Stainless steel
- Cast iron
- Hard chrome plated surfaces
Points to consider
- Leave around 0.2–0.5 mm grinding stock per face on hardened parts to clean up distortion.
- Thin parts can bow when released from the magnetic chuck; grinding both sides alternately helps.
- Specify flatness and parallelism separately from thickness where they matter.
- Grinding after hardening is standard for tool and die parts.
Frequently asked questions
Why grind instead of milling a flat surface?
Grinding achieves much tighter flatness, thickness and finish, and works on hardened steel that milling cannot cut economically.
How much grinding allowance should I leave?
Typically 0.2–0.5 mm per face for hardened parts, depending on size and expected distortion. Less is needed on unhardened parts.
Can non-magnetic materials be surface ground?
Yes, using vacuum chucks, vices or special fixtures instead of a magnetic chuck.