The SB method only works if there is some play between the chainring nuts (inner female part) and the holes in the crank spider and chainring. More often than not the chainring is so badly out of round that methods such as this are futile, and the only solution is to replace the chainring with a better one. The unbranded stock chainring on the Lasco cranks that came with my Moto Messenger was so bad, that even with chain adjusted with only about 1/8" play at its tightest position (should be more like 1/2" play), the chain could be removed from the chainring at its loosest position, which is dangerous. At the time I replaced it with another chainring, which completely eliminated the problem. The replacement chainring was a steel Sugino RD2 part, so we're not talking anything exotic here. I have since replaced the crankset with an Andel unit, which is nearly perfect with virtually no discernible variation in chain slack as the cranks are turned. Another benefit of better quality chainrings is that typically the teeth are machined more precisely, resulting in smoother and quieter chain engagement.