BCGControlBar Pro for MFC
UINT CBCGPChartAxis::m_nMaxTotalLines

Specifies how many major units an axis can display.

This property specifies the maximal number of major units an axis allowed to display. This number affects the major unit size, which also depends on maximal label size.

If you set this value to a fairly big number, the major unit size will depend only on a maximal label size (if neither "fixed interval width" mode, nor "fixed major unit" option is not set). Otherwise, the major unit size will be calculated as minimum between how many major units fits the axis with current label size and how many major units is allowed.

The default value for Y axis is 9, for X axis it's calculated as number of data points for categorized series, or unlimited for series with X componet set (which means that for X axis with X component set the number of major units always depends only on max label size).