you can use two tool for fitting a the crossbar with the down tube , a notcher will make the cross bar go in the down tube. also a press to create a oval bar where the crossbar will seat. make shure that the oval end of the downtube is 7/8 dimameter large (not long ). that should help increase your welding surface end create a cleaner looking bar. for photo i sugest you go check out affinity scooter on instagram !