A linear gauging device when attached to a chain saw bar will facilitate in the accurate measurement and swift successive cutting of a log into pre-determined uniform lengths of firewood. A chainsaw attachment consisting of an elongated resilient rod having one end fitted with a stabilizing cup and a locking stud, when extended through a single bore in the chainsaw bar, allows the effortless attachment to any chain saw bar. The locking stud fitted with a bore to receive a modified cotter pin thus performing a failsafe means of attachment. The rod is extended perpendicular to the cutting plane and lengthwise to the log. The opposing end of the rod is fitted with a large disc, when firmly locked against the end of the log, will position the chain saw cutting bar in the exact location of the measured length of cut. In contrast to the fixed measured length of the gauging rod, a variable length rod can be manufactured consisting of two rods, a hollowed outer rod and a telescoping inter rod. The outer rod having one bore perpendicular to the rod and extending through both sides of the hollowed rod. The inter rod having several perpendicular bores at two inch increments. This arrangement thus allows the gauging rod to be set at several different lengths by aligning desired inter rod bore with outer rod bore and inserting a modified cotter pin through the bores firmly locking the measured length adjustment in place.