If your chart is a column/area/line chart, double-click the x-axis and
in the Scale tab check 'Value (Y) axis crosses between categories.

If it is a XY scatter chart adjust the x-axis min/max values to taste.

In article ,
says...
I have a chart that plots body mass index, ie value on y axis, and dates on x
axis. I have also added a second category x as I have divided the chart into
horizonatl zones with different colors (ie underweight, overweight etc).

Things work fine except that when I plot, for instance, three dates (Jan 1,
Feb 1, March 1). The Jan point is right on the left side Y axis, the Feb is
mid way across the chart, and the March is on the other end of the chart
(right Y axis) I'd like to narrow down the spaces between each data point,
and also have some space at the beginning of the chart (ie the first point
shouldn't plot on the Y axis).

When I click on the data (format data point), "gap width" is greyed out, and
nothing is checked. When I check "Up/Down bars", the first point and teh
last point move in (away from the edges), and "gap width" becomes "ungreyed".
However, adjusting gap width does not affect the distance between the data
points.

Thanks