So I have a mostly parts-bin '74 Raleigh Grand Prix that I have been using as a lightweight commuter bike. I did the Sheldon Brown-esque bottom bracket conversion to cotterless from a cottered crank with bent wheels. The new cranks were an ebay purchase (vintage Bennotto) that came with a spindle that didn't fit my frame, so I pulled another spindle (3NN if I remember right) out of the parts bin at the co-op that had bearing races in the right spots when compared to my old cottered spindle. It ran fine for a while but now my chain is skipping and I can't upshift to the large chainring without fear of the chain going right over the edge. It's obvious that the chainrings are not perpendicular to the frame when I spin the pedals around and watch the distance between the front derailer and the chain.

My question is - what did I screw up? Is there a possibility of a mis-match between the square tapers on the crank and spindle? Did I just not crank the bolt down hard enough on the crank arm? Or did I manage to bang up my chainrings and bend them? I'm capable of fixing the mechanical issues but don't have the experience to know if there's an incompatibility issue that I'm fighting against.