21. perfect full caster-standoff

[challenge-bot] / 3d-printables / caster-standoff.scad

diff --git a/3d-printables/caster-standoff.scad b/3d-printables/caster-standoff.scad
index 39ab746242d86e49c82a429f4d01c44c481c0610..322f502be8f33027f49178ea3357dee1aa2f4d0b 100644 (file)
--- a/3d-printables/caster-standoff.scad
+++ b/3d-printables/caster-standoff.scad
@@ -7,8 +7,21 @@
 // use 10 ish for development, 60 or so for printing
 $fn = 60;
 
-standoff_radius = 14.732 / 2; // 0.580 / 2 inches from spec sheet
-standoff_height = 48; // eyeballed
+/* measured with calipers */
+ball_diameter = 12.7 + 0.80; // extra bit added for printing imprecision
+ball_radius = ball_diameter / 2;
+
+wall_thickness = 1;
+holder_floor = 3;
+holder_arms_length = 10;
+holder_height =
+  holder_floor + holder_arms_length + (11 / 16) * ball_diameter;
+
+holder_radius = ball_radius + wall_thickness;
+holder_diameter = holder_radius * 2;
+
+standoff_radius = holder_radius; // 0.580 / 2 inches from spec sheet
+standoff_height = 48 - holder_height; // eyeballed
 
 // eyeballed caster flange height, (0.580/5) inches, times 2 to be stronger
 caster_flange_height = 5;
@@ -45,14 +58,13 @@ module deck_flange_reinforcement(){
                 deck_flange_radius]);}}}}}
 
 module ball_holder(){
+  gap = wall_thickness * 4;
   difference (){
     cylinder(r = holder_radius, h = holder_height);
-    translate([0, 0, ball_radius + wall_thickness]){
+    translate([0, 0, ball_radius + holder_floor + holder_arms_length]){
       sphere(r = ball_radius);}
-    translate([0, 0, holder_height / 2 + wall_thickness]){
-      cube([holder_diameter + 0.1,
-            wall_thickness * 2,
-            holder_height],
+    translate([0, 0, holder_floor + (holder_height - holder_floor) / 2 + 0.5]){
+      cube([holder_diameter + 0.1, gap, holder_height - holder_floor + 0.1],
            center = true);}}}
 
 module caster_standoff(){
@@ -65,5 +77,4 @@ module caster_standoff(){
   translate([0, 0, standoff_height]){
     ball_holder();}}
 
-//caster_standoff();
-ball_holder();
+caster_standoff();