I am in the middle of overhauling a old mountain bike and I am down to the last disassemble - The 2 Crank arms from the chainring and frame. I have all the nuts I can find off the the crank arm ends but it still won't come apart. I thought maybe that the crankarm itself was screwed to the pin but I tried it without any luck. I even tried hammering. There is no sign of a screw holding it in place. I am stumped. Anyone have any insight?