From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Mon, 24 Jul 2023 18:02:39 +0000 (+0100)
Subject: topeak-mtx-tortec-expeditionrack-adapter: adjust for shear not rotate
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=7a4a7e9ed06d6921dcf2b6f9e8165232d03daeb1;p=reprap-play.git

topeak-mtx-tortec-expeditionrack-adapter: adjust for shear not rotate

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 49441be..f2bdf45 100644
--- a/topeak-mtx-tortec-expeditionrack-adapter.scad
+++ b/topeak-mtx-tortec-expeditionrack-adapter.scad
@@ -103,7 +103,10 @@ rack_shear_ratio = - front_to_rear_elevation_change / rear_to_front_distance;
 front_to_cross_rail =
   cross_rail_distance * sqrt(1 - rack_shear_ratio * rack_shear_ratio)
   - rear_bolt_to_front_bolt
-  - rear_to_cross_rail;
+  - rear_to_cross_rail
+  - sqrt( pow( cross_rail_distance * rack_shear_ratio, 2 )
+	  - pow(  front_to_rear_elevation_change, 2 ) )
+  ;
 
 brk_bolt_nut_top_y = -brk_nearbolt_recess_depth
   - brk_bolt_eff_len + brk_bolt_nut_th + brk_bolt_len_slop;
@@ -420,7 +423,7 @@ module RackForDemoCrosses(){
 	      ]) {
       translate([0,0,z])
 	linextr_x_yz(rack_rail_x, -rack_rail_x)
-	circle(r= rack_rail_dia/2, $fn=6);
+	circle(r= rack_rail_dia/2, $fn=8);
     }
   }
 }