Bubster - another reason you see so many bow bars on Poulan saws is the fact that Claude Poulan really cut his teeth manufacturing bow bars to ease the task of harvesting pulp wood. Many of the Poulan saws were used in the pulp wood industry and as a result were quite frequently equipped with the bow. If you take a close look at a bow bar you will see the inside of the bar is narrower than the outside edge where the groove is. This allows the bow bar to cut through most logs on the ground without pinching, and by the way, without requiring the operated to bend over to do it.
History of the Bow Chain Saw, the Pulpwood Saw.
by Tom Hawkins & Sons
The beginning's of the modern day bow type chain saw can be directly traced back to the orginal intended use of such a saw, back when it was first invented. The first bow shaped chain saw, appears to be the 1916 Swedish made Sector. But it and several other bow shaped saws that followed, were just that, bow shaped, but not a bow saw.
The bow saw as we refer to it here, was intended mainly for the purpose of a repetitive bucking situation. The term "bucking" is the process of cutting a log into sections, short or long pieces. Bow saws were designed mostly for the harvesting of pulpwood, used for the making of paper, usually cut into 4ft. lengths. The paper industry was huge and required large amounts of wood to make paper pulp. Paper mills provided many a woodsman the opportunity to earn a living by cutting pulpwood. The bow type chain saws have a bar that will not bind or pinch in the cut (kerf), it's a saw that was purposely designed to be pinchless.
Mark