-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 = 17;
+holder_height = holder_floor + holder_arms_length + (25 / 32) * 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