Fixed ball bearing chamfers.

readme.md

@@ -5254,6 +5254,7 @@ The origin of the rack is the left end of the pitch line and its width is below
 |:--- |:--- |
 | ```centre_distance(m, z1, z2, pa = 20)``` | Calculate distance between centres taking profile shift into account |
 | ```involute(r, u)``` | Involute of circle radius r at angle u in radians |
+| ```involute_gear_od(m, z, pa = 20)``` | involute gear outside diameter given modulus, tooth count and pressure angle |
 | ```involute_rack_tooth_profile(m, pa = 20, clearance = undef)``` | Calculate rack tooth profile given module and pressure angle |
 | ```involute_worm_profile(m, pa = 20, clearance = undef)``` | Calculate worm profile suitable for passing to thread() |
 | ```profile_shift(z, pa)``` | Calculate profile shift for small gears |

utils/gears.scad

@@ -46,6 +46,9 @@ function profile_shift(z, pa) = z ? max(1 - z * sqr(sin(pa)) / 2, 0) : 0; //! Ca
 function centre_distance(m, z1, z2, pa = 20) = //! Calculate distance between centres taking profile shift into account
     let(x1 = profile_shift(z1, pa), x2 = profile_shift(z2, pa)) m * (z1/2 + z2/2 + x1 + x2);
 
+function involute_gear_od(m, z, pa = 20) = //! involute gear outside diameter given modulus, tooth count and pressure angle
+    m * (z + 2 * profile_shift(z, pa) + 2);
+
 module involute_gear_profile(m, z, pa = 20, clearance = undef, steps = 20) { //! Calculate gear profile given module, number of teeth and pressure angle
     assert(z >= 7, "Gears must have at least 7 teeth.");
     d = m * z;                                                  // Reference pitch circle diameter

vitamins/ball_bearing.scad

@@ -52,21 +52,21 @@ module ball_bearing(type) { //! Draw a ball bearing
         rim_chamfer = rim / 6;
         rotate_extrude()
             hull() {
-                translate([or - rim / 2, 0])
-                    square([rim, h - 2 * rim_chamfer], center = true);
+                translate([or - rim, -h / 2 + rim_chamfer])
+                    square([rim, h - 2 * rim_chamfer]);
 
-                translate([or - rim / 2 - rim_chamfer, 0])
-                    square([rim - rim_chamfer, h], center = true);
+                translate([or - rim, -h / 2])
+                    square([rim - rim_chamfer, h]);
             }
 
         hub_chamfer = hub / 6;
         rotate_extrude()
             hull() {
-                translate([ir + hub / 2, 0])
-                    square([hub, h - 2 * hub_chamfer], center = true);
+                translate([ir, -h / 2 + hub_chamfer])
+                    square([hub, h - 2 * hub_chamfer]);
 
-                translate([ir + hub / 2 + hub_chamfer, 0])
-                    square([hub - hub_chamfer, h], center = true);
+                translate([ir + hub_chamfer, -h / 2])
+                    square([hub - hub_chamfer, h]);
             }
     }