Abstract: One or more replaceable cutting blade tips and a central mounting bar comprise a blade assembly. Each of the replaceable cutting blade tips can be selectively attached to the central mounting bar without the use of tools. During typical operation, the replaceable cutting blade tips snugly fit relative to the central mounting bar and little, if any, relative pivoting therebetween is evident. However, some relative pivoting can occur when exceptional loads are encountered by the replaceable cutting blade tips such as when an obstacle such as a rock is encountered. In such an instance, a tearable "zipper" is provided which allows the blade tip to "tear" its way through the zipper while pivoting, thus advantageously providing a means for dissipating energy. Also provided is a "family of bars" concept which reduces inventory, reduces tooling expenses, and facilitates efficient and correspondingly low cost blade tips due to the volumes possible.