[Tex/LaTex] the minimum cell’s table width

Question

I'm kind of stuck in the middle of nowhere because I want to make this table (48 columns I know it's huge… but I need this) fit in a4paper but it seems there is a cell's table minimum width, isn't it ? For instance, there is no difference between 1pt and 0.001pt.

Thanks for helping.

\documentclass[a4paper,12pt]{article}

\usepackage{array}

\begin{document}

\begin{table}[htp]
\begin{center}
    \begin{tabular*}{\textwidth}{| *{48}{>{\centering\arraybackslash}m{0.1pt}|}}
        \hline
         & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & \\
        \hline
    \end{tabular*}
\end{center}    
\end{table}

\end{document}

Answer 1

The is a minimum distance between columns which is called tabcolsep. You can set this to zero --- and then manage the thing manually:

\setlength{\tabcolsep}{0pt}

Look:

\documentclass[a4paper,12pt]{article}
\usepackage{array}
\begin{document}
\begin{table}[htp]
\begin{center}
    \setlength{\tabcolsep}{0pt}
    \begin{tabular*}{\textwidth}{| *{48}{>{\centering\arraybackslash}m{5pt}|}}
        \hline
         & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & \\
        \hline
    \end{tabular*}
\end{center}    
\end{table}
\end{document}

You have to consider the vertical line width (I think it's 0.4pt by default), and in this case you'll need some stretch to "fill the space" (it's underfull now), like:

 \setlength{\tabcolsep}{0pt}
    \begin{tabular*}{\textwidth}{| *{48}{%
            @{\extracolsep{\fill}}%
            >{\centering\arraybackslash} m{7pt}|%
            @{\extracolsep{\fill}}}%
        }
        \hline
         .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .& .\\
        \hline
    \end{tabular*}

For more complex distribution of space, maybe tabularx is a better option.