Working with Purchased and Multipurpose Parts - Autodesk Inventor 2010: No Experience Required - page 260

9. In the Create iMate dialog, set Type to Insert and pick the outer edge
of the hole in the housing, as shown in Figure 6.2.
FIGURE 6.2 Creating an Insert iMate
10. Click Apply to create the iMate and keep the dialog open.
11. Switch the constraint type to Angle, and pick the fl ange on the edge
of the housing, as shown in Figure 6.3.
FIGURE 6.3 Adding the Angle iMate constraint
12. Click OK to create the iMate and close the dialog.