From 39c27c9c41c48e64b97d881e1d2121eb6832a795 Mon Sep 17 00:00:00 2001
From: TQ Hirsch <thequux@thequux.com>
Date: Sun, 6 Mar 2022 14:01:50 +0100
Subject: [PATCH] Extended rear corners to make space for idler screws

---
 TODO.md    | 16 ++++++++--------
 parts.scad | 49 ++++++++++++++++++++++++++++++-------------------
 2 files changed, 38 insertions(+), 27 deletions(-)

diff --git a/TODO.md b/TODO.md
index 078ec1b..1cea65c 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,8 +1,8 @@
-## Mechanical
-
-* Lengthen rear corner frame holders
-* Add screw holes for feet in each corner
-* Add place to mount electronics (likely just an extra part)
-
-## Electronics
-
+## Mechanical
+
+* Add screw holes for feet in each corner
+* Add place to mount electronics (likely just an extra part)
+* add slot for motor electronic connection
+* Add screw holes for idler mounts in rear corner
+## Electronics
+
diff --git a/parts.scad b/parts.scad
index 1507fc0..e274212 100644
--- a/parts.scad
+++ b/parts.scad
@@ -5,15 +5,13 @@ include <units.inc>
 
 frame_size = 20;
 wall_thickness = 2;
-corner_size = 30;
+corner_size = 40; // length of mating surface between corner and frame
 // The length along each edge that the corner bracket takes.  I.e., if
 // you construct a frame of four corner brackets and 4 tubes of length
 // $L-$corner_size, the distance between opposite tubes' centerlines
 // will be $L.
 corner_offset = frame_size / 2 + wall_thickness;
 rail_diam = 8;
-// distance between centerline of rail and centerline of frame Y tube.
-yrail_offset = (frame_size + corner_size) / 2;
 
 ysled_extralen = frame_size; // on each end
 
@@ -24,10 +22,13 @@ belt_height2 = belt_height1 + belt_width + 2;
 // calculated
 
 ysled_rail_spacing = (sled_ysize);
-motor_shaft_xoffset = (corner_size - wall_thickness) / 2 + 1;
+motor_shaft_xoffset = 15;
 motor_mount_length_adjustment = 4;
 motor_mount_length = nema17_face + wall_thickness + motor_mount_length_adjustment;
 
+// distance between centerline of rail and centerline of frame Y tube.
+yrail_offset = motor_shaft_xoffset + pulley_sbend_offset;
+
 // Generates bar of length $l, centered on origin extending in +Z
 module tslot(l) {
   bom_item(printable = false, label = str("tslot(", l, "mm)"));
@@ -38,10 +39,10 @@ module tslot(l) {
 }
 
 // A corner, with tubes extending in +x and +y.
-module corner_base() {
+module corner_base(extension = wall_thickness) {
   odim = frame_size / 2 + wall_thickness;
-  ldim = frame_size / 2 + corner_size;
-
+  ldim = frame_size / 2 + corner_size + (extension - wall_thickness);
+  actual_corner_offset = frame_size / 2 + extension;
   cap_points = [
     [ -odim, -odim ], [ -odim, ldim ], [ odim, ldim ],
     [odim, odim], [ ldim, odim ],
@@ -52,31 +53,41 @@ module corner_base() {
         polygon(points = cap_points);
 
     // two bars...
-    translate([ -frame_size / 2, corner_offset, -frame_size / 2 ])
+    translate([ -frame_size / 2, actual_corner_offset, -frame_size / 2 ])
         cube([ frame_size, ldim, frame_size ]);
-    translate([ corner_offset, -frame_size / 2, -frame_size / 2 ])
+    translate([ actual_corner_offset, -frame_size / 2, -frame_size / 2 ])
         cube([ ldim, frame_size, frame_size ]);
-    translate([ corner_offset, corner_offset, -frame_size / 2 ])
-        cube([ ldim, ldim, frame_size ]);
-    // translate([-odim - 1, -odim - 1, 0])
-    // cube(ldim*2);
+
+    for (pos = [10, 30],
+         mirror_normal = [[0,1,0], [1,-1,0]]) {
+      mirror(mirror_normal)
+      translate([pos + actual_corner_offset, 0, -odim])
+      union() {
+        cylinder(d = 8, h=2, center=true);
+        cylinder(d = 5, h = odim);
+      }
+    }
   }
 }
 
+rail_holder_width = (yrail_offset - frame_size / 2 - wall_thickness) * 2;
+
 module rail_holder(in_x) {
   odim = frame_size / 2 + wall_thickness;
-  ldim = frame_size / 2 + corner_size;
+  box_size = (yrail_offset - odim) * 2;
+  assert(box_size == rail_holder_width);
+  ldim = frame_size / 2 + box_size;
   tube_offset = (corner_size) / 2 + wall_thickness;
   tube_rotation = in_x ? 90 : 0;
 
   translated_rail_offset = yrail_offset - frame_size / 2 - wall_thickness;
 
 
-  translate([ frame_size / 2 + wall_thickness, frame_size / 2 + wall_thickness, -frame_size / 2 - wall_thickness ]) {
+  translate([ odim, odim, -odim ]) {
     difference() {
       cube([
-        !in_x ? corner_size - wall_thickness : 10,
-        !in_x ? 10 : corner_size - wall_thickness,
+        !in_x ? box_size - wall_thickness : 10,
+        !in_x ? 10 : box_size - wall_thickness,
         wall_thickness * 2 + frame_size
       ]);
       translate(
@@ -291,7 +302,7 @@ module blcorner() {
   bom_item();
   render()
   rotate([ 0, 0, 270 ]) {
-    corner_base();
+    corner_base(extension = rail_holder_width);
     rail_holder(true);
   }
   translate([motor_shaft_xoffset + pulley_sbend_offset, 0, 0])
@@ -307,7 +318,7 @@ module brcorner() {
   bom_item();
   render()
   rotate([ 0, 0, 180 ]) {
-    corner_base();
+    corner_base(extension = rail_holder_width);
     rail_holder(false);
   }
   translate([-(motor_shaft_xoffset + pulley_sbend_offset), 0, 0])