Three-Hole Punch Screw
These two pieces had gotton separated from each other in my box of "unknowns."  See if you can tell whether their fracture surfaces go back together.

Click on the linked titles to see the corresponding animated models of the fracture surfaces created with Helicon Focus and Helicon 3D Viewer.
Bottom half - 45X
Top half - 40X
Three-Hole Punch Screw at 45X magnification
Top half of 3-hole punch screw at 40X magnification