I am trying to mount a metal fender on my bike that was formerly a cross bike. I explicitly moved to this one (used) because the "crossy", plastic ones tend to slip to one side or another, and are not long enough in either direction.
The fender came with four screws that are, I believe, translated to English as "Strive Bolts" (German: Strebenbolzen/Klemmschraube). In the below image, the screw will sink into the "center" ring, and thus the hole becomes tighter.
One centrally on each fender (see below) to connect the metal bar to the fender, and two to connect it near the wheel's center on the frame (back) / front fork, to be secured with a nut on the other side.
The holes in the frame/fork are threaded.
This gives me the following problem: Since the direction of the hole is somewhat predetermined by the angle from which the metal bars come, the suitable position for the strive bolt is only every 1/2 turn.
Now it seems to me that I either have it such that the metal bar is loose and will slip right out (and it did already on a pothole), or I turn it another half rotation before trying to insert the bar, and then the hole starts to get covered because the bolt "sinks" into the cover-thing (center, first picture) and I cannot fit the metal bar in at all anymore.
I also cannot screw the bolt further in after inserting the metal bar into it, because the metal bar is connected to the fender which is already mounted on top to the fork.
What am I missing? To me, it seems like the "strive bolts" are perhaps supposed to be inserted in a non-threaded hole on the fork where they can spin freely, then insert the metal bar in the bolt, and then lock the metal bar in the bolt by screwing the nut on the other side tighter and tighter, thus pulling the bolt in and closing the hole. Am I thus trying to combine two incompatible designs?