Horizontal boring machine is the most widely used type of boring machine. It is mainly hole processing, boring accuracy up to IT7, in addition to expanding the workpiece has been cast or machined holes, horizontal boring machine can also mill the plane, drilling, processing the outer circle of the end face and flange, as well as cutting threads, etc., mainly used in a single piece of small batch production and repair workshop, the roundness error of the processing hole does not exceed 5 microns, and the surface roughness is Ra0.63 ~ 1.25 microns. The main parameter of the horizontal boring machine is the spindle diameter.