Method for milling helical racks

When milling helical racks, which mounting methods are required to ensure the helix angle β? For each occasion? How can the clamping method be different in size when milling?
       The first method is to tilt the rack. After being clamped by this method, the reference side of the rack and the direction of the movement of the table form an included angle, and the included angle is the helix angle β of the workpiece. Each shift of the table should be equal to the normal pitch pn of the helical rack. This method is only suitable for helical racks with small helix angles.
       The second method is to set the reference side of the rack to be parallel to the moving direction of the table, and then turn the table so that the table can rotate the workpiece with a helix angle. When this kind of rotary table method is used to mill the inclined rack, each shift distance should be equal to the end face pitch pt of the helical rack, which is suitable for milling longer helical racks on the universal milling machine.