Make itty bitty mount more compact

By recessing the bolt holes for mounting the shelf and brackets, the
extruder can be raised to meet the bottom of the Prusa/Wilson
x-carriage. This gives a nice 31mm of z back.

The base plate and holes are now generated separately, and some of the
hole placement code is better (not by much...).

diff --git a/carriage adapter/itty-wilson.scad b/carriage adapter/itty-wilson.scad
index f91b69e..1bb60a5 100644 (file)
--- a/carriage adapter/itty-wilson.scad
+++ b/carriage adapter/itty-wilson.scad
@@ -38,25 +38,28 @@ use <MCAD/nuts_and_bolts.scad>
 
 $fn = 64;
 
+hole_tolerance = 0.6; // widen holes a bit, may still need to drill out
+
+// Size of mounting bolt heads so they can be recessed
+bolthead_depth = 1.6;
+bolthead_diameter = 5.5 + hole_tolerance;
+
 carriage_height = 64;
 carriage_width = 52;
 
 plate_width = 75; // wilson carriage is only 50mm wide!
-plate_depth = 6; // wilson default depth = 8, makerfarm = 6
-
-hole_tolerance = 0.25; // widen holes a bit, may still need to drill out
+plate_depth = 6 + bolthead_depth; // wilson default depth = 8, makerfarm = 6
 
 plate_cut_height = 6.5;
 plate_cut_width = 6;
-plate_cut_distance = 13;
-plate_cut_center = 25.1;
+plate_cut_distance = 13.3;
 plate_cut_y_offset = 27;
 plate_cut_bolt = 3 + hole_tolerance;
-plate_cut_x_bolt_offset = 10.5 + plate_cut_bolt / 2;
+plate_cut_x_bolt_offset = plate_cut_distance + plate_cut_bolt / 2;
 
 plate_extra_height = 4; // make plate a bit taller so it is structurally sound
 
-plate_height = plate_cut_height + plate_cut_y_offset + plate_extra_height; 
+plate_height = plate_cut_height + plate_cut_y_offset + plate_extra_height;
 
 lower_cut_y_offset = 5.33; // 5.325 in CAD
 lower_bolt_x_offset = 1.5 + plate_cut_bolt / 2;
@@ -67,71 +70,89 @@ carriage_hole_spacing = 23;
 carriage_clearance = 20; // holes are 20mm from bottom of plate
 carriage_y_offset =  plate_cut_y_offset + plate_cut_height + carriage_clearance;
 carriage_nut_depth = 3.2 + 3.2/2 + 0.1; // m4 nut depth + half of an m4 nut + tolerance
+carriage_offset = [(plate_width - carriage_width) / 2, 0 , 0];
 
 corner_radius = 3; // round off the corners to make it look nicer
 
-shelf_mount ();
-translate ([(plate_width - carriage_width) / 2, plate_height - plate_extra_height/2, 0]) carriage_mount ();
 
-// mount to wilson x-carriage
-module carriage_mount () {
-     difference () {
-         linear_extrude (height = plate_depth, convexity = 8) {
-              // outline of plate + bolt holes
-              difference () {
-                   translate ([corner_radius, corner_radius, 0]) {
-                        minkowski () {
-                             square ([carriage_width - corner_radius*2, carriage_height - corner_radius]);
-                             circle (r = corner_radius);
-                        }
-                   }
+difference () {
+     union () {
+         translate (carriage_offset) carriage_mount_base ();
+         shelf_mount_base ();
+     }
+     translate (carriage_offset) carriage_mount_holes ();
+     shelf_mount_holes ();
+}
 
-                   #translate ([(carriage_width - carriage_hole_spacing) / 2, (carriage_height - carriage_hole_spacing) /2, 0])
-                   for (x = [0, carriage_hole_spacing], y = [0, carriage_hole_spacing]) {
-                        translate ([x, y, 0]) circle (d = carriage_bolt);
-                   }
+// mount to wilson x-carriage
+module carriage_mount_base () {
+     linear_extrude (height = plate_depth, convexity = 8) {
+         // outline of plate + bolt holes
+         translate ([corner_radius, corner_radius, 0]) {
+              minkowski () {
+                   square ([carriage_width - corner_radius*2, carriage_height - corner_radius]);
+                   circle (r = corner_radius);
               }
          }
-         // after extruding, cut out spaces for M4 hex nuts.
-         translate ([(carriage_width - carriage_hole_spacing) / 2, (carriage_height - carriage_hole_spacing) /2, plate_depth - carriage_nut_depth]) {
-              for (x = [0, carriage_hole_spacing], y = [0, carriage_hole_spacing]) {
-                   translate ([x, y, 0]) linear_extrude (height = carriage_nut_depth + 0.01) nutHole (size = carriage_bolt, proj = 1);
-              }
+     }
+}
+
+module carriage_mount_holes () {
+     #translate ([(carriage_width - carriage_hole_spacing) / 2, (carriage_height - carriage_hole_spacing) /2, 0])
+     for (x = [0, carriage_hole_spacing], y = [0, carriage_hole_spacing]) {
+         translate ([x, y, -0.1]) cylinder (d = carriage_bolt, h = plate_depth+1);
+     }
+
+     // after extruding, cut out spaces for M4 hex nuts.
+     translate ([(carriage_width - carriage_hole_spacing) / 2, (carriage_height - carriage_hole_spacing) /2, plate_depth - carriage_nut_depth]) {
+         for (x = [0, carriage_hole_spacing], y = [0, carriage_hole_spacing]) {
+              translate ([x, y, 0]) linear_extrude (height = carriage_nut_depth + 0.01) nutHole (size = carriage_bolt, proj = 1);
          }
      }
 }
 
 // mount for makerfarm extruder shelf
-module shelf_mount () {
-     linear_extrude (height = plate_depth, convexity = 8) {     
-         difference () {
-              translate ([corner_radius, corner_radius, 0]) {
-                   minkowski () {
-                        square ([plate_width - corner_radius*2, plate_height - corner_radius*2]);
-                        circle (r = corner_radius);
-                   }
+module shelf_mount_base () {
+     linear_extrude (height = plate_depth, convexity = 8) {
+         translate ([corner_radius, corner_radius, 0]) {
+              minkowski () {
+                   square ([plate_width - corner_radius*2, plate_height - corner_radius*2]);
+                   circle (r = corner_radius);
               }
+         }
+     }
+}
 
+module shelf_mount_holes () {
+     depth = plate_depth+0.2;
+     translate ([0, 0, -0.1]) {
               // upper shelf mount
-              translate ([0, plate_cut_y_offset, 0]) {
-                   for (x = [-0.01, plate_cut_width + plate_cut_distance, plate_cut_width*2 + plate_cut_distance + plate_cut_center, plate_cut_width*3 + plate_cut_distance*2 + plate_cut_center + 0.01])
-                        #translate ([x - hole_tolerance/2, 0, 0]) square ([plate_cut_width + hole_tolerance, plate_cut_height]);
+              translate ([plate_cut_width/2, plate_cut_y_offset, 0]) {
+                   for (x = [-0.001, plate_cut_width + plate_cut_distance,
+                             plate_width - plate_cut_width + 0.001, plate_width - plate_cut_width*2 - plate_cut_distance])
+                        #translate ([x, plate_cut_height/2, 0]) cube ([plate_cut_width + hole_tolerance, plate_cut_height, depth], center = true);
+
+                        // looks like the bolt is at the midpoint between the cut outs
+                        for (x = [plate_cut_x_bolt_offset - plate_cut_width, plate_width - plate_cut_x_bolt_offset])
+                             translate ([x, plate_cut_height / 2, 0]) {
+                                  #cylinder (d = plate_cut_bolt, h = depth);
+                                  cylinder (d = bolthead_diameter, h = bolthead_depth+0.1);
+                             }
 
-                   // looks like the bolt is at the midpoint between the cut outs
-                   for (x = [plate_cut_x_bolt_offset, plate_width - plate_cut_x_bolt_offset])
-                        translate ([x, plate_cut_height / 2, 0]) circle (d = plate_cut_bolt + hole_tolerance);
               }
 
               // lower shelf mount
               translate ([0, lower_cut_y_offset, 0]) {
                    for (x = [plate_cut_width/2 - 0.01, plate_width - plate_cut_width/2 + 0.01]) {
                         // lower cut out is closer to 6mm than 6.5mm in cad drawings
-                        translate ([x, plate_cut_height/2, 0]) square ([plate_cut_width, plate_cut_height - 0.5], center=true);
-                   }
+                        translate ([x, plate_cut_height/2, 0]) cube ([plate_cut_width, plate_cut_height - 0.5, depth*2], center=true);
+              }
                    // I think the intention is for the screw holes to be centered over the cut out
                    for (x = [lower_bolt_x_offset, plate_width - lower_bolt_x_offset])
-                        translate ([x, plate_cut_height + lower_bolt_y_offset, 0]) circle (d = plate_cut_bolt + hole_tolerance);
+                        translate ([x, plate_cut_height + lower_bolt_y_offset, 0]) {
+                             cylinder (d = plate_cut_bolt, h = depth);
+                             cylinder (d = bolthead_diameter, h = bolthead_depth+0.1);
+                        }
               }
          }
-     }
 }