Wheel hexes with setscrews?

[Atomic Skull]

So you plan on drilling our the existing holes and tapping threads into them to utilize set screws in place of the pins? Or new holes combined with the existing pins?

New holes in the center of the hex with rolled threads instead of cut for added strength (I recently learned a bit about rolled threads vs cut threads, rolled require a more precise tap hole but swage the threads out of the metal and result in stronger threads in soft metals like aluminum). You could leave the pin in but depending on the amount of slop between the hex and the bearing it might defeat the purpose. That said it would keep the hex from wobbling on the shaft though in that case you'd only really need a single M4 setscrew and not a pair of M5's and you wouldn't really need a flat either. It *is* a viable option to eliminate hub wobble, in that case you could skip the shims altogether, or just get it "close enough". The whole point of the M5 setscrews is that they are beefy enough to handle that sort of torque.

Even a pair of m4 setscrews is enough to handle the torque from a 7kw motor or even a 10kw motor on a large heli and that's with a helical pinion that exerts significant axial torque in addition to the rotational torque. I have actually seen a helical pinion slip axially when someone tried to install it without adding a flat to the shaft. The flat is key to the setscrew staying put.

EDIT: Actually I might just go for the second option of using an "anti wobble" setscrew and leave the pin. That way you don't need to worry about grinding down that last bit of shimming just make sure the side to side play isn't too excessive. It's the wheel wobble that's most annoying the sideways slop would be unnoticeable if that were gone.