mudguard-bracket: Add bracket tie hole

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

diff --git a/mudguard-bracket.scad b/mudguard-bracket.scad
index 7fabb79480275b9756f82e3ffa8b50e4aeba4fc7..79ec84e9f63d4ecc9a49e08971edd72da1b0caa2 100644 (file)
--- a/mudguard-bracket.scad
+++ b/mudguard-bracket.scad
@@ -29,6 +29,8 @@ retainer_th = 3;
 clamp_main_th = 4;
 clamp_depth = 4;
 bracket_buttress = 2.5;
+bracket_tie_hole = 6;
+bracket_tie_around = 4;
 
 retainer_x_gap = 0.25;
 retainer_big_gap = 2.5;
@@ -46,6 +48,7 @@ bracket_bot_z = screw_hole_z - beam_h/2;
 bracket_top_z = screw_hole_z + beam_h/2;
 bracket_bot_xsz = tubeswidth_at_z(bracket_bot_z) + tube_dia * 2.5;
 bracket_top_xsz = tubeswidth_at_z(bracket_top_z) + tube_dia * 2.5;
+bracket_tie_outer_r = bracket_tie_hole/2 + bracket_tie_around;
 
 wing_top_ea_x = -tubeswidth_top/2 - wings_main_th/2;
 
@@ -191,6 +194,25 @@ module Bracket(){ ////toplevel
       linextr_y_xz(bracket_top_z - bracket_buttress, bracket_top_z)
        rotate(180)
        BracketButtressPlan();
+      translate([ 0,
+                 bracket_top_z,
+                 wings_height ]) {
+       linextr(-beam_th, 0) {
+         difference(){
+           hull(){
+             translate([0, bracket_tie_hole/2])
+               intersection(){
+                 circle(r = bracket_tie_outer_r);
+                 rectfromto([ -100, 0 ], [ 100,100 ]);
+               }
+             rectfromto([ -bracket_tie_outer_r, 0 ],
+                        [ +bracket_tie_outer_r, 1 ]);
+           };
+           translate([0, bracket_tie_hole/2])
+             circle(r = bracket_tie_hole/2);
+         }
+       }
+      }
     }
     linextr(-1, wings_height+1) {
       for (m=[0,1])