more generous back side cutout

just wanted a wider opening in there, but I'm not entirely pleased
with the resulting code, though given the late hour I'll leave with it.
Maybe until I revert this commit or rework that part altogether.

1 files changed, 16 insertions, 7 deletions

diff --git a/another.scad b/another.scad
index f54c5cd..b80d0d0 100644
--- a/another.scad
+++ b/another.scad
@@ -229,204 +229,213 @@ module the_extruder(
        mirror([0,0,1]) {
         translate([0,0,st_thickshell])
         hull() for(o=[0,spring_d]) translate([0,-o,0])
         rotate([0,0,30])
         cylinder(d=st_nut_d+st_nut_d_tolerance,h=st_nut_h+st_nut_h_tolerance,$fn=6);
         translate([0,0,-1]) cylinder(d=st_screw_d+st_screw_d_tolerance,h=fsw+2,$fn=fnd*(st_screw_d+st_screw_d_tolerance));
         bigd = spring_d+spring_d_clearance;
         hf = (bigd-st_screw_d-st_screw_d_tolerance)/2;
         translate([0,0,st_thickshell+st_nut_h+st_nut_h_tolerance+st_thinshell-epsilon])
         cylinder(d1=st_screw_d+st_screw_d_tolerance,d2=bigd,
          h=hf+epsilon, $fn=fnd*bigd);
         translate([0,0,st_thickshell+st_nut_h+st_nut_h_tolerance+st_thinshell+hf-epsilon])
         cylinder(d=bigd,h=fsw+1,$fn=fnd*bigd);
        }
       }
      }
     } // translate
     
     // pushfit bracket
     translate([0,0,filament_elevation])
     rotate([0,0,45]) translate([pulley_d/2,0,0])
     rotate([-90,0,0])
     translate([0,0,mount_d/sqrt(2)/2+mount_screw_d-gearbox_d/2/*TODO:*/]) {
      pfbl = pf_h(pf)+gearbox_d/2; //TODO:
      if(pf_smooth) {
       pfbd = pf_d(pf)+2*pf_shell;
       hull() {
        cylinder(d=pfbd,h=pfbl,$fn=pfbd*fnd);
        translate([-epsilon/2,0,0]) {
         cube(size=[epsilon,filament_elevation,pfbl-filament_elevation+pfbd/2]);
         mirror([0,1,0])
         cube(size=[epsilon,body_h-filament_elevation,pfbl-body_h+filament_elevation+pfbd/2]);
        }//translate
       }//hull
      }else{
       pfb2a = pf_d(pf)+2*pf_shell; pfba = pfb2a/2;
       pfbd = pfb2a/cos(30);
       pfbs = pfb2a*tan(30);
       cylinder(d=pfbd,h=pfbl,$fn=6);
       translate([-pfbs/2,0,0]) {
        hull() {
         translate([0,-pfba,0]) cube(size=[pfbs,pfb2a,pfbl]);
         cube(size=[pfbs,filament_elevation,pfbl-filament_elevation+pfba]);
         mirror([0,1,0])
         cube(size=[pfbs,body_h-filament_elevation,pfbl-body_h+filament_elevation+pfba]);
        }//hull
       }//translate*/
      }//if(pf_smooth)
     }//translate rotate translate rotate translate
    }//union (first child of difference)
 
    // protrusion
    translate([0,0,-1])
    cylinder(d=protrusion_d+protrusion_tolerance_h,h=protrusion_h+protrusion_tolerance_v+1,$fn=fnd*(protrusion_d+protrusion_tolerance_h));
    // mount screw holes
    for(zr=[0:90:359]) rotate([0,0,zr]) translate([mount_d/2,0,0]) {
     translate([0,0,mount_screw_l-mounthole_depth/2-(bridges?layer_height:-epsilon)])
     mirror([0,0,1])
     cylinder(d=mount_screw_d+mount_screw_d_tolerance,
              h=mount_screw_l-mounthole_depth/2+1,
              $fn=fnd*(mount_screw_d+mount_screw_d_tolerance));
     translate([0,0,mount_screw_l-mounthole_depth/2])
     cylinder(d=mount_screwhead_d,h=body_h+1,$fn=fnd*mount_screwhead_d);
    }//for
    // pushfit
    translate([0,0,filament_elevation])
    rotate([0,0,45]) translate([pulley_d/2,0,0])
    rotate([-90,0,0])
    translate([0,0,mount_d/sqrt(2)/2+mount_screw_d+epsilon])
    rotate([0,0,180]) {
     pushfit(pf);
     cylinder(d=filament_guide_d,h=gearbox_d,center=true,$fn=fnd*filament_guide_d);
     translate([0,-filament_guide_d/2/sqrt(2),0])
     rotate([0,0,45])
     cube(size=[filament_guide_d/2,filament_guide_d/2,gearbox_d],center=true);
    }//rotate translate rotate translate rotate translate
    // pulley
    cylinder(d=pulley_d+pulley_clearance,h=body_h+1,$fn=fnd*(pulley_d+pulley_clearance));
    // leverspace
    hull() for(x=[0,gearbox_d])
    rotate([0,0,45])
    translate([x,0,ls_z-ls_h/2])
    cylinder(d=idler_d+idler_clearance,h=ls_h,$fn=fnd*(idler_d+idler_clearance));
 
    // idler clearance
    a=cos(45)*(pulley_d+idler_d)/2;
    b=mount_d/2-a;
    x=sqrt(pow(a,2)+pow(b,2));
    translate([mount_d/2,0,ls_z])
    intersection() {
     r = x+idler_d/2+idler_clearance;
     cylinder(r=r,h=ls_h,center=true);
     translate([-r-1,0,-ls_h/2-1]) cube(size=[2*r+2,r+1,ls_h+2]);
    }
 
    // back side cutout
-   a0 = asin((mount_screwhead_d+2*extrusion_width)/mount_d);
+   // XXX: this is somewhat ugly and potentially bugged,
+   //      but I want to sleep.
+   a0_ = atan(
+    (mount_d/sqrt(2)/2+mount_screw_d+pf_h(pf)+gearbox_d/2)
+    /
+    (
+     pulley_d/2-
+     (pf_d(pf)+2*pf_shell)/2/cos(30)
+    )
+   );
+   a0 = -135 + ( (a0_>0) ? a0_ : 180+a0_ );
    a1 = atan((longwing-lever_thickness/2)/(gearbox_d/2));
-   translate([0,0,ls_z]) hull() {
+   translate([0,0,ls_z]) difference() {
     rotate([0,0,-180+a0])
     rotate_extrude(angle=a1-a0)
     translate([0,-ls_h/2])
     square([sqrt(pow(gearbox_d/2,2)+pow(longwing-lever_thickness/2,2))+1,
-            ls_h]);
-    cylinder(d=bore_d/2/*TODO:recalculate angles based on this,
-                         too lazy to do that now*/,
-             h=ls_h,center=true);
-   }
+           ls_h]);
+    translate([-mount_d/2,0,0])
+    cylinder(d=gearbox_d-mount_d,h=ls_h+2,center=true,$fn=fnd*(gearbox_d-mount_d));
+   }//difference translate
    
    rotate([0,0,-45])
    translate([0,0,ls_z-ls_h/2])
    cube(size=[gearbox_d,gearbox_d,lever_thickness+lever_v_clearance]);
    translate([0,0,ls_z-ls_h/2]) {
     translate([mount_screwhead_d/2,0,0])
     mirror([0,1,0])
     cube(size=[gearbox_d,gearbox_d/2+1,lever_thickness+lever_v_clearance]);
    }
    //translate([-mount_d/2,-longwing,filament_elevation])
    if(!tensioner) /* XXX: this seems to be bullshit, but it's so old, that it's historical bullshit */
    translate([mount_d/2,-longwing,filament_elevation])
    rotate([0,-90,0]) difference() {
     cylinder(d=spring_d+spring_d_clearance,h=spring_lc+spring_dl,$fn=fnd*(spring_d+spring_d_clearance));
     translate([0,0,spring_lc+spring_dl]) sphere(d=spring_d*3/4,$fn=fnd*spring_d*3/4);
    }
 
   }//difference
 
   if(supports) intersection() {
    difference() {
     translate([0,0,ls_z-ls_h/2-epsilon])
     cylinder(d=gearbox_d,h=ls_h+2*epsilon,$fn=fnd*gearbox_d);
     cylinder(d=pulley_d+pulley_clearance,h=body_h+1,$fn=fnd*(pulley_d+pulley_clearance));
    }
    // supports
    // TODO: hardcoded stuff below…
    if(false) { // parallel
     for(y=[-gearbox_d:4:gearbox_d])
      translate([0,y-extrusion_width/2,0])
      cube(size=[gearbox_d,extrusion_width,body_h]);
    }else{ // radial
     for(zr=[-65:(65+50)/7:50])
      rotate([0,0,zr]) translate([0,-extrusion_width/2,0])
      cube(size=[gearbox_d,extrusion_width,body_h]);
    }
   }
 
  }//body module
 
  module springpad() {
   smalld=st_screw_d+st_screw_d_tolerance+2*extrusion_width;
   bigd = spring_d+spring_d_clearance/2;
   hf = (bigd-smalld)/2;
   translate([-gearbox_d/2+st_thickshell+st_nut_h+st_nut_h_tolerance+st_thinshell+1,-longwing,filament_elevation])
   rotate([0,90,0]) difference() {
    union() {
     cylinder(d1=smalld,d2=bigd,h=hf,$fn=fnd*bigd);
     translate([0,0,hf-epsilon])
     cylinder(d=bigd,h=hf*2,$fn=fnd*bigd);
     translate([0,0,3*hf])
     sphere(d=spring_d*3/4,$fn=fnd*spring_d*3/4);
    }
    translate([0,0,-epsilon])
    cylinder(d=st_screw_d+st_screw_d_tolerance,h=2*hf+epsilon,$fn=fnd*(st_screw_d+st_screw_d_tolerance));
   }
  }
 
  module knob() {
   ch = knob_indent_d/2;
   translate([0,0,body_h+epsilon]) {
    mirror([0,0,1]) translate([0,0,-epsilon]) {
     difference() {
      cylinder(d=pulley_d,h=knob_bore_l,$fn=fnd*pulley_d);
      translate([0,0,-1]) difference() {
       cylinder(d=bore_d+knob_bore_d_tolerance,h=knob_bore_l+2);
       translate([-bore_d/2-1,bore_dd-bore_d/2+knob_bore_d_tolerance/2,-1])
       cube([bore_d+2,bore_d/2,knob_bore_l+4]);
      }
     }
    }
    difference() {
     union() {
      cylinder(d1=gearbox_d-2*ch,d2=gearbox_d,h=ch+epsilon,$fn=fnd*gearbox_d);
      translate([0,0,ch])
      cylinder(d=gearbox_d,h=knob_h-2*ch+epsilon,$fn=fnd*gearbox_d);
      translate([0,0,knob_h-ch])
      cylinder(d1=gearbox_d,d2=gearbox_d-2*ch,h=ch,$fn=fnd*gearbox_d);
     }
     for(a=[0:360/knob_indents:359]) rotate([0,0,a])
      translate([0,gearbox_d/2,-1])
      cylinder(d=knob_indent_d,h=knob_h+2,$fn=fnd*knob_indent_d);
    }
   }
  }//knob module
 
  module debug() {
   difference() {
    children();
    if(debug) {
     // spring tensioner debug cutout
     if(tensioner) // TODO: collaps copypasted transformations
     translate([-gearbox_d/2,0,0])
     translate([0,-longwing,ls_z]) rotate([0,-90,0])
     translate([0,-lever_thickness/2-1,-gearbox_d])
     cube(size=[body_h/2+1,lever_thickness/2+1,gearbox_d+2]);