diff --git a/X Carriage/X Carriage.scad b/X Carriage/X Carriage.scad
index 23a4342..355fc3e 100644
--- a/X Carriage/X Carriage.scad	
+++ b/X Carriage/X Carriage.scad	
@@ -1,4 +1,5 @@
 include <../lib/common.scad>;
+include <../lib/examples.scad>;
 
 thickness = 6;
 width = 65;
@@ -20,6 +21,7 @@ module base() {
         small_holes();
         belt_holes();
         endstop_holes();
+        wheel_clerance();
     }
 }
 
@@ -33,6 +35,17 @@ module big_holes() {
 
 }
 
+module wheel_clerance() {
+    diameter = 30;
+    diameter2 = 7;
+    translate([diameter2 / 2 + 5, diameter2 / 2 + 7, thickness])
+        cylinder(d = diameter, h = thickness * 10);
+
+    translate([width - (5 + diameter2 / 2), diameter2 / 2 + 7, thickness])
+        cylinder(d = diameter, h = thickness * 10);
+
+}
+
 module small_holes() {
     diameter = 5;
 
@@ -57,21 +70,25 @@ module belt_holes() {
 
 module mount() {
     translate([(width - 35) / 2, 0]) {
+
         rotate([90, 0, 0]) {
             difference() {
                 union() {
                     block_with_fillet(35, 30, thickness, 10);
                     cube([35, 10, thickness]);
+                    rotate([180, 0, 0])
+                        translate([0, - 20, 0])
+                            prism(35, 20, 23);
                 }
 
                 union() {
                     translate([2.5 + 2, 20, 10])
                         rotate([180, 0, 0])
-                            screw_mount(length = 10, nut_size = 6, screw_size = 3, nut = "hexagon");
+                            screw_mount(length = 10, nut_size = 6, screw_size = 3, nut = "hexagon", nut_height = 30);
 
                     translate([2.5 + 25, 20, 10])
                         rotate([180, 0, 0])
-                            screw_mount(length = 10, nut_size = 6, screw_size = 3, nut = "hexagon");
+                            screw_mount(length = 10, nut_size = 6, screw_size = 3, nut = "hexagon", nut_height = 30);
                 }
             }
         }
@@ -79,20 +96,6 @@ module mount() {
     }
 }
 
-module screw_mount(length, nut_size, screw_size, nut = "none") {
-    translate([screw_size / 2, screw_size / 2, 0]) {
-        cylinder(d = screw_size + 3, h = screw_size);
-        cylinder(d = screw_size, h = length);
-        if (nut == "hexagon") {
-            translate([0, 0, length - 3])
-                cylinder(d = nut_size, h = 3, $fn = 6);
-        } else if (nut == "square") {
-            translate([- nut_size / 2, - nut_size / 2, length - 3])
-                cube([nut_size, nut_size, 3]);
-        }
-    }
-}
-
 module endstop_holes() {
     diameter = 2;
     translate([width - (diameter / 2 + 3), diameter / 2 + 16, - 0.1])
diff --git a/X Carriage/X Carriage.stl b/X Carriage/X Carriage.stl
index f4937fb..e2a5253 100644
Binary files a/X Carriage/X Carriage.stl and b/X Carriage/X Carriage.stl differ
diff --git a/lib/common.scad b/lib/common.scad
index 4e4afcc..5a458c0 100644
--- a/lib/common.scad
+++ b/lib/common.scad
@@ -1,18 +1,18 @@
-module screw_mount(length, nut_size, screw_size, nut = "none") {
+module screw_mount(length, nut_size, screw_size, nut = "none", nut_height = 3) {
     translate([screw_size / 2, screw_size / 2, 0]) {
         cylinder(d = screw_size + 3, h = screw_size);
         cylinder(d = screw_size, h = length);
+
         if (nut == "hexagon") {
             translate([0, 0, length - 3])
-                cylinder(d = nut_size, h = 3, $fn = 6);
+                cylinder(d = nut_size, h = nut_height, $fn = 6);
         } else if (nut == "square") {
             translate([- nut_size / 2, - nut_size / 2, length - 3])
-                cube([nut_size, nut_size, 3]);
+                cube([nut_size, nut_size, nut_height]);
         } if (nut == "square+") {
             translate([- nut_size / 2, - nut_size / 2, length - 3])
-                cube([nut_size+100, nut_size, 3]);
+                cube([nut_size + 100, nut_size, nut_height]);
         }
-        
     }
 }
 
diff --git a/lib/examples.scad b/lib/examples.scad
new file mode 100644
index 0000000..bd64356
--- /dev/null
+++ b/lib/examples.scad
@@ -0,0 +1,6 @@
+module prism(l, w, h) {
+    polyhedron(
+    points = [[0, 0, 0], [l, 0, 0], [l, w, 0], [0, w, 0], [0, w, h], [l, w, h]],
+    faces = [[0, 1, 2, 3], [5, 4, 3, 2], [0, 4, 5, 1], [0, 3, 4], [5, 2, 1]]
+    );
+}
\ No newline at end of file