In the design of xk2116 CNC gantry boring and milling machine, through the analogy analysis of the same type of products of foreign advanced manufacturers and combined with the previous design experience, it is decided to adopt two fulcrum supports for the main shaft. The front support is a set of d3182132 double row short cylindrical roller bearing and a set of c2268132 double row thrust ball bearing, with the accuracy of grade C; the rear support is a set of d3182128 double row short cylindrical roller bearing, with the accuracy of grade D.