Grinding — removing material
The coarsest of the three. Grinding removes material aggressively — used to level welds, remove burrs and correct dimensional excess. It leaves a rough surface that needs further work before it's a finish.
Polishing — refining the surface
Progressively finer abrasives smooth out the marks grinding left behind. The directional grain of a No.4 brushed finish (see our finish codes guide) is created at this stage.
Buffing — the final shine
Uses soft wheels with fine compound to produce a bright, reflective surface with no visible abrasive marks — this is how an 8K mirror finish is achieved. Buffing barely removes material; it's about optical smoothness.
Why the sequence matters
You can't skip stages. A mirror finish requires proper grinding and progressive polishing beforehand — attempting to buff a poorly ground surface just produces a shiny surface with the underlying defects still visible. This is a good thing to understand when inspecting finished work.