# Heavy arrow tips for xy-pic

Arrows in xy-pic have narrow heads, but I need heavy tips for my graphs. I tried the following arrow definition, but the tip of the arrow enters into the circle of graph node.

\documentclass{report}
\usepackage[all]{xy}

\newdir{|>}{%
!/4.5pt/@{|}*:(1,-.2)@^{>}*:(1,+.2)@_{>}}

\begin{document}
$\xygraph{ !{<0cm,0cm>;<2cm,0cm>:<0cm,2cm>::} !{(0,0)}*+=[o]+[F]{1}="1" !{(1,0)}*+=[o]+[F]{2}="2" "1":@{|>}"2" }$
\end{document}