diff --git a/leather/axis.py b/leather/axis.py
index fe97242..7e4f9eb 100644
--- a/leather/axis.py
+++ b/leather/axis.py
@@ -79,7 +79,7 @@ def to_svg(self, width, height, scale, orient):
             )
             title.set('text-anchor', 'middle')
             title.set('font-family', theme.axis_title_font_family)
-            title.set('font-size', six.text_type(theme.axis_title_font_size))
+            title.set('font-size', str(theme.axis_title_font_size))
             title.text = self._name
 
             group.append(title)
@@ -163,7 +163,7 @@ def to_svg(self, width, height, scale, orient):
             )
             label.set('text-anchor', text_anchor)
             label.set('font-family', theme.tick_font_family)
-            label.set('font-size', six.text_type(theme.tick_font_size))
+            label.set('font-size', str(theme.tick_font_size))
 
             value = tick_formatter(value, i, tick_count)
             label.text = str(value)