WEBSee the chain-pitch-and-gauge chart below. What is Chain Gauge? Chain Gauge is the Drive Link's thickness where it fits into the bar groove. The gauge of the chain and the gauge of the bar must match. OREGON® has several gauges for chain saws - such as, .043” (1,1mm), .050” (1,3mm), .058” (1,5mm) and .063” (1,6mm).