Looking to connect a rear rack. I've read all the threads in all the forums on this topic, but I still think the most sensible thing is to connect the rack arms to the seatpost clamp. I tried to make my own longer seatpost skewer by threading a wheel skewer down far enough to cut it off and use as a seatpost skewer, but the rod is obviously made of hardened steel since my threading die wouldn't cut threads in it. It completely stuck after about 3-4 turns beyond the existing threads. I suppose that I could go to a machinist and get it done, but the solution of a longer seatpost skewer seems too obvious for no one to have done it by now.
Since I needed to use the rack last fall, I improvised an made a seatpost collar that got the job done for that ride, but I'd like to do it differently the next time.
So what is the product that you are aware of?