use polyholes some places so holes print better... should be applied …

…to the rest of the printer as well

src/bearing.scad

@@ -5,6 +5,8 @@
 // http://www.reprap.org/wiki/Prusa_Mendel
 // http://prusamendel.org
 
+use <polyholes.scad>
+
 bearing_diameter = 15;
 
 module horizontal_bearing_base(bearings=1){
@@ -65,8 +67,9 @@ module vertical_bearing_base(){
 }
 
 module vertical_bearing_holes(){
-  translate(v=[0,0,-1]) cylinder(h = 62, r=bearing_diameter/2, $fn = 60);
-  rotate(a=[0,0,-70]) translate(v=[8,0,31.5]) cube(size = [5,1,62], center = true);
+  translate(v=[0,0,-1]) poly_cylinder(h = 62, r=bearing_diameter/2);
+  rotate(a=[0,0,-70]) translate(v=[bearing_diameter/2-1,-0.5,-1]) cube(size = [thinwall*2,1,62]);
+
 }
 
 difference(){

src/polyholes.scad

@@ -0,0 +1,42 @@
+//
+// Mendel90
+//
+// GNU GPL v2
+// [email protected]
+// hydraraptor.blogspot.com
+//
+// See http://hydraraptor.blogspot.com/2011/02/polyholes.html
+//
+function sides(r) = max(round(4 *r),3);
+function correctedRadius(r,n) = 0.1 + r / cos(180 / n);
+function correctedDiameter(d) = 0.2 + d / cos(180 / sides(d / 2));
+
+module polyCircle(r, center = false) {
+    n = sides(r);
+    circle(r = correctedRadius(r,n), $fn = n, center = center);
+}
+
+module poly_circle(r, center = false) {
+	polyCircle(r, center);
+}
+
+module polyCylinder(r, h, center = false) {
+    n = sides(r);
+    cylinder(h = h, r = correctedRadius(r,n), $fn = n, center = center);
+}
+
+module poly_cylinder(r, h, center = false) {
+	polyCylinder(r,h,center);
+}
+
+module polydCylinder(r, center = false) {
+    n = sides(r);
+    r = correctedRadius(r,n);
+    cylinder(h = h, r = r, $fn = n, center = center);
+    translate([0, -r, 0])
+        cube([r, 2 * r, h]);
+}
+
+module poly_d_cylinder(r, center = false) {
+	polydCylinder(r,center);
+}

src/x-end.scad

@@ -6,6 +6,7 @@
 // http://prusamendel.org
 
 use <bearing.scad>
+use <polyholes.scad>
 rod_distance = 45;
 
 module x_end_base(){
@@ -46,7 +47,7 @@ translate(v=[-15,-41.5,6]) rotate(a=[-90,0,0]) pushfit_rod(8.1,50);
 // Top pushfit rod
 translate(v=[-15,-41.5,rod_distance+6]) rotate(a=[-90,0,0]) pushfit_rod(8.1,50);
 // Nut trap
- translate(v=[0,-17,-0.5]) cylinder(h = 4, r1=3.3, r2=2.8, $fn=25);
+ translate(v=[0,-17,-0.5]) poly_cylinder(h = 4, r=2.6, $fn=25);
  translate(v=[0,-17,3]) rotate([0,0,30]) cylinder(h = 10, r=4.5, $fn = 6);
 }
 
@@ -63,7 +64,7 @@ x_end_plain();
 
 
 module pushfit_rod(diameter,length){
- cylinder(h = length, r=diameter/2, $fn=30);
+ poly_cylinder(h = length, r=diameter/2);
  difference(){
  	translate(v=[0,-diameter/2.85,length/2]) rotate([0,0,45]) cube(size = [diameter/2,diameter/2,length], center = true);
  	translate(v=[0,-diameter/4-diameter/2-0.4,length/2]) rotate([0,0,0]) cube(size = [diameter,diameter/2,length], center = true);