E se eliminassi la tabella più esterna e facessi in questo modo?


<table class="td1" style="width:30%; float:left">
<tr>
<td></td>
<td></td>
<td></td>
</tr>


<table class="td1" style="width:30%; float:left">
<tr>
<td></td>
<td></td>
<td></td>
</tr>
</table>

<table class="td1" style="width:30%; float:left">
<tr>
<td></td>
<td></td>
<td></td>
</tr>
</table>