The field of the invention is concrete cutting and the invention relates more particularly to the cutting of a chamfer adjacent a 90.degree. cut made through a reinforced concrete wall. Such 90.degree. cuts are typically made by utilizing a wall saw mounted on a trolley. The trolley rides along a track which typically includes a rack and the trolley typically includes a gear which meshes with the rack and moves the saw slowly along the wall forming a 90.degree. cut. One such saw assembly is shown in U.S. Pat. No. 3,763,845. Another concrete cutting saw referred to as a "wall saw" is shown in U.S. Pat. No. 5,588,418.
Stonecutting saws have been known for many years and a stonecutting saw which includes two separate saw blades is shown in U.S. Pat. No. 896,702. A stonecutting saw, including a 45.degree. saw, is shown in U.S. Pat. No. 2,187,299. These two saws work simultaneously and the monument is mounted in such a way that the saw must travel past the end of the monument before the second saw finishes its cut.
Typically, the prior art has been concerned with the forming of the 90.degree. cut through the wall. After a 90.degree. cut has been made, it is architecturally important that the new opening have the same edges, or edges which are aesthetically related to the edges which are already formed in other openings in the concrete wall. It is well known that in order to form an opening in a concrete tip-up wall, it is beneficial to chamfer the opening so that when the wall is removed from the form from which it is cast, there is no cracking or removal of concrete at the opening. The chamfer solves this problem. However, the concrete wall-cutting saws leave a sharp 90.degree. cut. Typically, a chamfer is formed by grinding along the sharp edge. Such grinding is time consuming, messy and provides a cut which is not a perfect 45.degree. angle. Another approach is to use a Skillsaw type of saw, hand held, and the blade is tilted at a 45.degree. angle. Once again, the cut is not perfectly straight because of the hand held nature of the saw and it is also a slow time consuming and messy process.