Ok, here is the situation: I just replaced the bottom bracket on my bike and just now attempted to put the cranks on. The cranks are square-tapered and are clearly matching. The right one fits the bb just fine. But the left one goes on about two thirds of the way and doesn't want to move any further. I tried to pound it on with a rubber mallet, but that didn't seem to make a bit of difference. I've heard about square-tapered cranks that were deformed to become too loose - but too tight??

I did dig out the old bb to see how things were there. The taper on one of the side was scratched up more than the other, suggesting that a crank must've been forced onto it. Should I just pound much harder or will the ruin the bb and the crank? Or is there some trick to help push the bloody thing on? Is this something common (perhaps normal) or is it something extremely unusual and bad?