I thinking about replacing my cup and cone bottom bracket with a cartridge unit. I replaced my crankset this season with a shimano M151 set which is square taper. It looks as if the shimano UN54 bottom bracket will work nicely in this application. The present installation has a spindle which uses a nut to attach the crank, not a bolt, so I will need to purchase the bolts as well. After looking over the different types of bolts available I'm not sure which ones I need so I'm looking for some advice in this area. Also I'm wondering if my present crank extractor tool will work ok with the new bottom bracket, it is a "Lifu Cotterless Crank Extractor". What will the center of the tool push against if it is a female end on the bottom bracket?