Getting x axis to cross both y axes at zero

BenSaw Let's say you want to plot two lines. One with values between 100 and -30 on the primary axis. The other series has values ranging from 7 to -5, on the secondary axis.

Excel will set the boundaries for both axes automatically. The primary from 120 to -40, crossing the X.axis at zero and the secondary from 8 to -6 and the zeroes indeed do not line-up. Even though the 2nd axis setting has an option to have the horizontal axis cross at a particular value, it doesn't seem to do anything. At least not on my Excel (currently on Excel for MS365 on a Mac).

To fix that, you need to set the max and min boundaries of the 2nd axis manually, so that the ratio between them is the same as for the primary axis.

For the first axis the ratio is -3 (i.e. 120 / -40 ). Now set the 2nd axis to have a minimum of -5 and the max at 15. That results in the same ratio ( 15 / -5 = -3 ). Or perhaps you would prefer 18 and -6. As long as you keep the ratio at -3, the zeroes will line up. You may have to play with the major and minor units as well to get the labels right.

See attached file for an example.