I'm putting a new tange sealed bottom bracket, 68mm, into a NOS frame i just bought. The frame is a Sekine, 68mm bottom bracket. It's never had a bottom bracket in it before and the BB i have does not thread in very smoothly. Anyway the bb won't go in flush and the bb does not sit straight in the shell. What to do, do the threads need to be reamed maybe? Or is this situation just a case of a faulty frame?