From 92eb30d719e83005a6e4f881988b968c419c5342 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Thu, 22 Nov 2018 00:55:32 +0000
Subject: [PATCH] poster-tube-lid: Break out SomeStrap (nfc)

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 poster-tube-lid.scad | 49 ++++++++++++++++++++++++++------------------
 1 file changed, 29 insertions(+), 20 deletions(-)

diff --git a/poster-tube-lid.scad b/poster-tube-lid.scad
index bdad0c2..8528673 100644
--- a/poster-tube-lid.scad
+++ b/poster-tube-lid.scad
@@ -458,6 +458,26 @@ module ImplHeadCupTest(){ ////toplevel
       ImplHeadCup();
 }
 
+module SomeStrap(){
+  // children(0) is to add, (1) subtract
+  difference(){
+    union(){
+      cylinder(r=sm_outer_rad, h=sm_main_width);
+      StrapMountProtrusion(smc_cnr_c_x + sm_closure_cnr,
+			   smc_max_y,
+			   sm_closure_cnr);
+      children(0);
+    }
+    translate([0,0,-1])
+      cylinder(r=sm_inner_rad, h=sm_main_width+2);
+    translate(smc_pos)
+      StrapMountBolt(10);
+    translate(smc_pos)
+      cube([ sm_bolt_tighten_allow, 40,100 ], center=true);
+    children(1);
+  }
+}
+
 module StrapMountBolt(l_delta){ ///toplevel
   // positioned relative to smc_pos
   translate([(smc_bolt_nut_eff_thick - sm_bolt_head_thick)/2,
@@ -492,28 +512,17 @@ module StrapMountProtrusion(half_x, max_y, cnr){
 }
 
 module StrapMount(){ ////toplevel
-  difference(){
-    union(){
-      cylinder(r=sm_outer_rad, h=sm_main_width);
-      StrapMountProtrusion(smc_cnr_c_x + sm_closure_cnr,
-			   smc_max_y,
+  SomeStrap(){
+    rotate([0,0,180]){
+      StrapMountProtrusion(strap_hoop_inside/2 + strap_hoop_thick,
+			   strap_hoop_thick,
 			   sm_closure_cnr);
-      rotate([0,0,180]){
-	StrapMountProtrusion(strap_hoop_inside/2 + strap_hoop_thick,
-			     strap_hoop_thick,
-			     sm_closure_cnr);
-	translate(smc_pos +
-		  [0,0, sm_main_width] +
-		  strap_hoop_thick * [ 0, 0.5, -1.0 ])
-	  StrapHoop();
-      }
+      translate(smc_pos +
+		[0,0, sm_main_width] +
+		strap_hoop_thick * [ 0, 0.5, -1.0 ])
+	StrapHoop();
     }
-    translate([0,0,-1])
-      cylinder(r=sm_inner_rad, h=sm_main_width+2);
-    translate(smc_pos)
-      StrapMountBolt(10);
-    translate(smc_pos)
-      cube([ sm_bolt_tighten_allow, 40,100 ], center=true);
+    union(){ };
   }
 }
 
-- 
2.30.2