The use of carbide tipped circular saw blades on gas powered cutting-off machines is strictly prohibited. Among other things, the teeth of  such a blade can catch in the work-piece and cause reactive forces,  
including kickback. The heavier weight of such blades can increase  kickback forces, and the aggressive tooth design can cause more severe injuries from blade contact. Please note that according to OSHA's Directorate of Compliance Programs from 1999, portable machines using circular saw blades would become "the functional equivalent of  a circular saw" and would, therefore, require guards for both the upper and lower portions of the blade. For the above mentioned reasons, Amana Tool(r) does not authorize the use of the carbide tipped circular saw blades on all gas powered cutting-off machines, and, in fact, strongly warns against it.