How to choose the grit sequence on a glass straight-line edger

A straight-line edger is a sequence of problems being solved in order. The rough station removes the most material and sets the geometry. The medium station removes the damage the rough station left behind. The fine and polishing stations remove the damage the medium station left behind. Skip a step and the damage never comes out — you just make it glossier.

For 4–6 mm float glass on a typical 9-wheel machine, a workable sequence is #80–#100 rough, #120–#150 medium, #240–#320 fine, then resin and felt with cerium oxide. On 19 mm laminated glass the rough grit is usually one step coarser (#60–#80) because the interlayer loads the wheel differently and the removal rate matters more, but the polishing end stays the same.

Two rules that save most people money. First, never jump more than two grit steps between stations — the finer wheel cannot remove the previous station's subsurface damage efficiently, so it glazes and you lose both life and finish. Second, match the bond to the station: metal bond for rough and medium where you need form retention, resin for fine, and felt or wool for polish.