\documentclass[letterpaper, 10pt]{article} % for letter size paper 
% 215.9mm × 279.4mm
\usepackage{tikz}


\begin{document}
\pagestyle{empty}

\begin{tikzpicture}[remember picture, overlay]

\tikzset{normal lines/.style={gray, very thin}} 
\tikzset{margin lines/.style={gray, thick}} 
\tikzset{mm lines/.style={gray, ultra thin}} 
\tikzset{strong lines/.style={black, very thin}} 
\tikzset{master lines/.style={black, very thick}} 
\tikzset{dashed master lines/.style={loosely dashed, black, very thick}} 

\node at (current page.south west){
  \begin{tikzpicture}[remember picture, overlay]

    \draw[style=normal lines,step=0.25in] (0,0) grid +(8.5in,11in); 
    \draw[style=margin lines] (1in,0)--(1in,11in);
    \draw[style=margin lines] (7.5in,0)--(7.5in,11in);

  \end{tikzpicture}
};
\end{tikzpicture}


\end{document}
