Create an XY series with a point at each location along the hidden axis where you want a tick mark. Hide the markers for this series, and add short error bars that extend into the chart (you can’t get them outside the plot area, but it doesn’t matter if there’s no axis line). Format these error bars so they look like good tick marks.

A nice trick is to place a value in a cell to use as the error bar length, and set the custom error bar length to this cell. You can easily adjust the error bars by changing the value in this cell, without going through the dialog multiple times.

Is there a way to show tick marks without showing the axis line? I’ve seen charts done this way I believe in the NY Times with column graphs, and it makes for a very clean presentation, but so far I haven’t been able to figure out how to do it in Excel without resorting to using a dummy x,y series, which then ties up the secondary axis. Is there something I’m missing?

Thanks, for all the great posts and advice,
Chris