A picture tells a thousand words!
[MENTION=158672]FBinNY[/MENTION] - I am a Bikesmith Cotter Press advocate - but not because using a hammer (with adequate crank arm support) is not effective: You are, (as usual) 100% right-on about the efficacy of using a hammer, and you are certainly one of the most knowledgeable guys on this forum, so I would not presume to contradict you, but the real reason why I no longer use one (a hammer) is because I'm a little eye-hand uncoordinated when it comes to swinging a claw hammer in close proximity to a valuable, or virtually irreplaceable, 70 year old chain ring.

More people than are willing to admit would be far better served by using a cotter press for that said-same reason.