I've got to make a couple of dome nuts for a 20mm wheel spindle on a set of leading link forks on a bike, I've got a piece of 30mm brass hex bar which would make nice dome nuts, would brass be strong enough?
Depends on the design of the forks. If it has a solid swing arm, IE its the swing arm thats stopping the wheel moving off the verticle I'd say OK. If these are chopper forks where the wheel is supported between two independant fork legs, I'd say brass would be questionable as there is a lot of flex and movement at the wheel spindle.