diff --git a/vitamins/hygrometer.scad b/vitamins/hygrometer.scad
index 0e64b85..e445aff 100644
--- a/vitamins/hygrometer.scad
+++ b/vitamins/hygrometer.scad
@@ -34,15 +34,16 @@ hygrometer_hole_r = 21.3;
 slot_w = 5.5;
 
 module hygrometer_hole(h = 0) { //! Drill the hole for a hygrometer
-    round(cnc_bit_r) {
-        intersection() {
-            drill(hygrometer_hole_r, h);
+    extrude_if(h)
+        round(cnc_bit_r) {
+            intersection() {
+                drill(hygrometer_hole_r, 0);
 
-            rotate(30)
-                square([slot_w + 2 * cnc_bit_r, 100], center = true);
+                rotate(30)
+                    square([slot_w + 2 * cnc_bit_r, 100], center = true);
+            }
+            drill((od + 0.2) / 2, 0);
         }
-        drill((od + 0.2) / 2, h);
-    }
 }
 
 function hygrometer_or() = flange_d / 2; //! The outside radius of a hygrometer
@@ -54,13 +55,13 @@ module hygrometer() { //! Draw a hygrometer
         color(grey(30))
             rotate_extrude()
                 polygon([
-                    [0, 0],
-                    [aperture_d / 2, 0],
-                    [aperture_d / 2, flange_t],
-                    [flange_d2 / 2,   flange_t2],
-                    [flange_d / 2,    flange_t],
-                    [flange_d / 2,    0],
-                    [od / 2,          0],
+                    [0,                0],
+                    [aperture_d / 2,   0],
+                    [aperture_d / 2,   flange_t],
+                    [flange_d2 / 2,    flange_t2],
+                    [flange_d / 2,     flange_t],
+                    [flange_d / 2,     0],
+                    [od / 2,           0],
                     [od / 2,          -h],
                     [0,               -h]
                 ]);