Posted by Today I countersunk the little trailing edge wedge piece (7-6: Step 12).
I used the drill press because I wanted consistency, and I thought it might be a little hard to hand-hold the countersink cage against the little wedge, at an angle, and be flush at all times.
The countersink holes need to be perpendicular to each face of the wedge, which is at a slight angle. My solution, in addition to using the drill press, was to use a scrap piece of wedge matching the opposite angle of the wedge I was drilling. This results in rotating the face of the wedge I’m drilling into a horizontal plane (imagine the profile view of the two wedges making a “Z” shape).
Builder's Log 