Editing Circular saw (section)

==Sawmill blades==
[[Image:Sawmill Circular Saw Blade.jpg|thumb|Portable sawmill circular saw blade about {{cvt|60|cm|ft}} diameter.]]

Originally, circular saws in mills had smaller blades and were used to resaw lumber after it passed through an "up and down" (muley or sash) saw leaving both vertical and circular saw marks on different sides of the same piece. These saws made it more efficient to cut small pieces such as lath.
After 1813 or 1822 saw mills use large circular saws, up to {{convert|3|m}} in diameter. Large saws demand more power than up-and-down saws and did not become practical for sawing timbers until they were powered by steam engines. They are either left or right-handed, depending on which side of the blade the plank falls away from. [[Sawfiler#Circular saw benching|Benching]] determines which hand the saw is. Saws of this size typically have a [[shear pin]] hole, off axis, that breaks if the saw is overloaded and allows the saw to spin free. The most common version is the [[ITCO]] (insert tooth cut-off) which has replaceable teeth. Sawmill blades are also used as an alternative to a radial arm saw.