It's the front fork. I suppose I will drill out the fork and get a recessed nut. However, on a non-recessed setup, there is a washer with a shape that hugs the curve of the back of the fork. A recessed nut, without such a washer, would contact only at the two left/right sides of the curve on the back of the fork, right? What keeps this from rocking, without having the contact of the specially curved washer used for non-recessed setups? Would you not need the recessed nut to make purchase 360 degrees around the drilled-out hole?