The thread i think your refering to is normally used when you want to extract the crank, you screw the crank extractor tool there, or you could use some middleburn self extracting crank bolts. The other thread would be for the pedals, 9/16. The bb would fit, not completely sure what shell size your frame would require, hopefully someone else can solve that. also you would need to get the splined cranks to go with that bb.