The spindle head has a reinforced structure with bones, and the contact length ratio between the spindle head and the column is appropriate to provide a stable support for the spindle;
The structure is reinforced with ribs in the spindle head, and the contact length ratio between the spindle head and the column is appropriate, which provides the solid support of the spindle;
The main shaft head is reinforced by tendons and bones, and the contact length ratio between the spindle head and the column is appropriate to provide stable support for the main shaft;<br>