How to alter the gap between bars in a Flex barchart

I wanted to make the gap between bars in a Flex barchart smaller. Maybe this seems so obvious to other Flex programmers that there is no need to write anything on the web about it, but for me the lack of documentation on this kind of formatting was like a bout of rigorous head-against-wall banging. There were entries dating back years with people asking the question of how to do this on forums but no answers.  Eventually I found the horizontalAxisRatio property of the chart. This property according to the docs:

public var horizontalAxisRatio:Number = 0.33

Determines the height limit of the horizontal axis. The limit is the width of the axis times this ratio.

The default value is 0.33.

So I made the height and ratio different numbers and looked at the results until settling on .005. The result:

If I've missed the documentation on this somewhere and you can point me to it, please do!

Happy Flexing!