diff --git a/bearing.scad b/bearing.scad
index 4b0b20d..b4ba296 100644
--- a/bearing.scad
+++ b/bearing.scad
@@ -8,12 +8,23 @@
 include <units.scad>
 include <materials.scad>
 
+// Example, uncomment to view
+//bearing_test();
+//bearing_hole_test();
+
 module bearing_test(){
     bearing();
     bearing(pos=[5*cm, 0,0], angle=[90,0,0]);
     bearing(pos=[-2.5*cm, 0,0], model=Bearing688);
 }
 
+module bearing_hole_test(){
+    difference(){
+      translate([0, 0, 3.5]) cube(size=[30, 30, 7-10*epsilon], center=true);
+      bearing(outline=true);
+    }
+}
+
 BEARING_INNER_DIAMETER = 0;
 BEARING_OUTER_DIAMETER = 1;
 BEARING_WIDTH = 2;
@@ -27,27 +38,29 @@ function bearingWidth(model) = model[BEARING_WIDTH];
 function bearingInnerDiameter(model) = model[BEARING_INNER_DIAMETER];
 function bearingOuterDiameter(model) = model[BEARING_OUTER_DIAMETER];
 
-module bearing(pos=[0,0,0], angle=[0,0,0], model=SkateBearing, material=Steel, sideMaterial=Brass) {
+module bearing(pos=[0,0,0], angle=[0,0,0], model=SkateBearing, outline=false,
+                material=Steel, sideMaterial=Brass) {
   w = bearingWidth(model);
-  innerD = bearingInnerDiameter(model);
+  innerD = outline==false ? bearingInnerDiameter(model) : 0;
   outerD = bearingOuterDiameter(model);
   
   innerRim = innerD + (outerD - innerD) * 0.2;
   outerRim = outerD - (outerD - innerD) * 0.2;
   midSink = w * 0.1;
 
-  color(material)  
-    translate(pos)
-      rotate(angle) {
-        difference() {
-          // Basic ring
-          Ring([0,0,0], outerD, innerD, w, material, material);
+  translate(pos) rotate(angle) union() {
+    color(material)  
+      difference() {
+        // Basic ring
+        Ring([0,0,0], outerD, innerD, w, material, material);
 
+        if (outline==false) {
           // Side shields
           Ring([0,0,-epsilon], outerRim, innerRim, epsilon+midSink, sideMaterial, material);
           Ring([0,0,w-midSink], outerRim, innerRim, epsilon+midSink, sideMaterial, material);
         }
       }
+  }
 
   module Ring(pos, od, id, h, material, holeMaterial) {
     color(material) {
diff --git a/units.scad b/units.scad
index b50cdc9..62662a9 100644
--- a/units.scad
+++ b/units.scad
@@ -20,5 +20,5 @@ M8 = 8*mm;
 
 
 // When a small distance is needed to overlap shapes for boolean cutting, etc.
-epsilon = 0.0001*mm;
+epsilon = 0.01*mm;