How can you customize the line widths of the axes and borders on a JMP plot?

[#1]

I see options to change the width of a fit line or reference lines, but I haven't found a way to increase the

thickness of the very thin default lines that make up plot borders and axes.

[#2 · Accepted solution]

If you want the x -axis thicker, double click on the y-axis and then add a reference line whose value corresponds with the value of the x-axis line that you want to be thicker.  You then increase the thickness by increasing the value of "Line Style" in the Y Axis Setting pop-up.  You can also change the color.  This will overlay your selection over the existing x-axis line.

I don't think you can do anything with the chart border other than have it selected or not selected in your preferences.