annular ring 23 represented in dashed lines is then forced or shrunk onto the intermediate tapered portion 29 of main shaft 19 as shown in solid lines in fig3 once in the final position shown in fig3 and 4 the stub shaft 20 is machined along the abutment surface 31 of the annular ring 23 machining is also done on the inner shaft portion 25 of the main shaft 19 to form a shoulder 32 by reducing the overall diameter of the inner shaft portion 25 as shown in fig5 the removed portions of annular ring 23 and inner shaft portion 25 from the machining process are represented in dashed lines in fig5 by performing the machining function the abutment surface 31 is exactly flush with the shoulder 32 this allows the annular ring 23 to fit tightly and snugly in abutment with the exterior flat surface of the hub 11 as shown in detail in fig2 and 6 once the structure is completely bolted together as shown in fig2 and 6 it will be appreciated that the hub 11 prevents the main shaft 19 from moving to the left this is primarily because of the abutment of shoulder 32 against the hub 11 additionally the tapered surfaces 29 on the main shaft 19 and 30.