hardware stores usually have a hex head bolt that would work. the only down side is that the threads would be different from skate kingpins so you need to pick up a new nut. also you might not be able to use a standard skate tool to tighten/loosen since the the new nut might be a different size. lucky for me, my local skateshop still stocks the specific kingpin to work for my stage 8s, they aint cheap though running like $4 a pop but if that means i can still run the stage 8s, its a small price to pay. next time im there, ill ask them where they source them and ill pass the info onto you. are you in the states?