diff --git a/gears.scad b/gears.scad
index 983d848..6315955 100644
--- a/gears.scad
+++ b/gears.scad
@@ -1774,7 +1774,7 @@ module worm_gear(
         difference() {
             vnf_polyhedron(vnf, convexity=teeth/2);
             if (shaft_diam > 0) {
-                cylinder(d=shaft_diam, h=worm_diam, center=true);
+                cylinder(h=2*thickness+1, r=shaft_diam/2, center=true, $fn=max(12,segs(shaft_diam/2)));
             }
         }
         children();