topeak-mtx-tortec-expeditionrack-adapter: wip

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/topeak-mtx-tortec-expeditionrack-adapter.scad b/topeak-mtx-tortec-expeditionrack-adapter.scad
index f3e5e3bb8a130c1afc202264e051154e5f13c00a..4a75e91e36a290f0e9afa4ed24659aa5a7e94f22 100644 (file)
--- a/topeak-mtx-tortec-expeditionrack-adapter.scad
+++ b/topeak-mtx-tortec-expeditionrack-adapter.scad
@@ -28,6 +28,11 @@ brk_bolt_dia = 4.0 + 0.5;
 brk_nearbolt_recess_dia = 8.86 + 1.5;
 brk_nearbolt_recess_depth = 1.09 + 0.25;
 
+brk_bolt_eff_len = 11.78 - 1.0; // inside of recess, to end of bolt
+brk_bolt_len_slop = 2.0;;
+brk_bolt_nut_th = 3.89;
+brk_bolt_nut_across_flats = 7.86 + 0.50;
+
 brk_overall_w = 90.07;
 
 main_sz_y = 20;
@@ -58,6 +63,11 @@ strap_barrel_x = rack_width_inner/2 + strap_barrel_dia/2;
 
 rack_shear_ratio = rear_elevation_nominal / rear_to_front_distance;
 
+brk_bolt_nut_top_y = -brk_nearbolt_recess_depth
+  - brk_bolt_eff_len + brk_bolt_nut_th + brk_bolt_len_slop;
+                      
+brk_bolt_nut_r = brk_bolt_nut_across_flats/2 / cos(360/12);
+
 module GraspElevation(){
   hull(){
     translate([ grasp_large_x, adapt_main_top_y - grasp_large_r ])
@@ -134,6 +144,12 @@ module BoltHole(){
 
   linextr_y_xz( -brk_nearbolt_recess_depth, 10)
     circle(brk_nearbolt_recess_dia/2);
+
+  linextr_y_xz( -100, brk_bolt_nut_top_y ) {
+    circle( r= brk_bolt_nut_r, $fn = 6 );
+    translate([ 0, brk_bolt_nut_across_flats/2 ])
+      circle( r=brk_bolt_nut_r/2, $fn = 4);
+  }
 }
 
 module Principal(){