Feed Screw, Y-Axis 

In your instruction manual, this part appears on the parts list as:

Item No	Models
170	BusyBee CX611 Craftex Small Mill Various SX3 SIEG Small Mill
171	Grizzly G0463 Grizzly Small Mill Harbor Freight 93885 Central Machinery Small Mill Various X3-US SIEG Small Mill Woodstock International M1110 Shop Fox Small Mill
271	Grizzly G0619 Grizzly Small Mill Various SX3 SIEG Small Mill

Click your model to see the complete parts list.