What accuracy does surface grinding give?

About ±0.005 mm on thickness and very good flatness on suitable parts, with surface finishes around Ra 0.2–0.8 µm.

Can a surface grinder grind aluminium?

Yes, with fixtures (the magnet does not hold it) and suitable wheels, but aluminium is usually finished by milling instead.

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Surface grinder

Also called: surface grinding machine, flat grinder, CNC surface grinder, hydraulic surface grinder

A surface grinder finishes flat surfaces with a spinning abrasive wheel while the part, held on a magnetic chuck, moves back and forth beneath it. It brings plates, dies and hardened parts to close thickness and flatness, about ±0.005 mm, with a fine finish.

Quick facts

Holding: Magnetic chuck (steel and iron parts); fixtures or vacuum for others
Typical accuracy: About ±0.005 mm on thickness
Surface finish: About Ra 0.2–0.8 µm
Sizes: Given by table length × width, e.g. 600 × 300 mm
Works on: Hardened and soft steel, cast iron, carbide (with diamond wheels)
Types: Reciprocating table (common) or rotary table

Typical work

Die plates, punches and press tool parts after hardening
Gauge blocks, parallels and flat precision parts
Mould plates and base plates
Squaring blocks before wire cut
Regrinding worn tools and dies

Tips

Leave about 0.1–0.3 mm per face for grinding after hardening
Thin parts can bend on the magnet and spring back: tell the shop the flatness you need
Non-magnetic materials (aluminium, stainless 304) need fixtures

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Materials

Questions

What accuracy does surface grinding give?: About ±0.005 mm on thickness and very good flatness on suitable parts, with surface finishes around Ra 0.2–0.8 µm.
Can a surface grinder grind aluminium?: Yes, with fixtures (the magnet does not hold it) and suitable wheels, but aluminium is usually finished by milling instead.

The figures on this page are typical values for guidance, written by Diemeco from standard engineering practice. They are not a specification: confirm grades and properties with the relevant standard or the supplier's mill test certificate, and tolerances with your workshop. Last checked 8 October 2026.