The factory side plate angle (as controlled by the top plate filing angle ) was arrived at after much experimentation. All the standard angles of cutter teeth are the more-or-less best compromises for typical conditions of cutting typical wood. Some slight changes can be made to accomodate non-typical cutting conditions. A top plate filing angle of 45 degrees would cause the teeth to try to dive sideways into the sides of the kerf and cut a wider kerf, just as an excessive hook in the top plate will cause the teeth to "porpoise" vertically in the cut. The factory tooth configuration can in general be improved only by providing a keener cutting edge, just as with mass-produced cutlery. A brand new chain can be improved by making the cutting edges sharper, but drastic changes to the angles and shape of the tooth will not gain anything, in my opinion.
