In order to change the width of the bottom border of the first row of a natural table to 2bp, I can do

\setupTABLE[row][1][after={\hrule width\hsize height 2bp}]

and I have tried doing

\setupTABLE[column][1][after={\vrule height\vsize width 2bp}]

to change the width of the right border of the first column, but this does not work.  I would appreciate some expertise on this.

Thanks,

Troy Henderson