there's no reason wood dowel wouldn't work just fine. you might find nylon rod at McMaster Carr but ordering it and then waiting for it to come would hardly be worth it,.....just use wood dowel. the only caution is that the nylon dowel might be metric (assuming Chinese built ARF),....6mm. (.236") slightly smaller than 1/4". but wood dowel sand easily, just take your time and check their fit often. the pins are nylon simply because they are cheaper to get than wood pins. wood pins requires more machinery and labor to make them and there's plenty of empty gallon milk jugs to melt down for the injection die machines.