Microsoft Word Tables: How make some vertical lines double?

Select the cells on either side of the border you want to be a double line. Then, on the Table Design tab, click on the Border Styles dropdown to select a double line:

Finally, click on the Border dropdown and choose Inside Vertical Border to apply the double lines to the border between the selected cells:

The paintbrush leads to piecemeal changes that make for complex document structures.

Using the inside vertical border command does the same thing with a simpler underlying structure. That makes for easier editing. I think it is similar to the difference between using direct and style-based formatting on text.

John is right.

I had never done a double border.

First pick the Border style. This does nothing to your border but sets up the next step.

Then in the Borders menu pick the inside vertical border.

It will set the border per the selected style.

Do NOT use the Border Painter... that way lies untold frustration!

You could make a double line by creating a very thin blank column with borders on both sides.

If you simply need emphasis, though, you can increase the width of the Border.

• Tables

There are lots of border styles to choose from. The problem is selecting exactly which borders one wants to widen or double, etc. The tool tip at "Border Styles" blithely says I can "Format specific borders in [my] table using a common style", as though this were a no-brainer. In my current ignorance I see no way to do this other than laboriously selecting particular groups of cells and going to "Borders" and choosing "right side" or "left side" and so on, which in my experience so far has led me to make lots of mistakes that I had to correct.

Hmm... I just noticed a paintbrush tool that may enable one to 'paint' the particular borders one wants to select. So I'll look into that...