2 files changed, 40 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index 9444a03..31135cb 100644
--- a/Makefile
+++ b/Makefile
@@ -13,3 +13,3 @@ clean:
 stl-another-%:
-        $(MAKE) another-$*-{body,lever}.stl
+        $(MAKE) another-$*-{body,lever,knob}.stl
 
@@ -19,2 +19,4 @@ another-%-lever.stl: another-%.scad another.scad
         $(OPENSCAD_BIN) $(OPENSCAD_FLAGS) -D 'what="lever"' -o "$@" "$<"
+another-%-knob.stl: another-%.scad another.scad
+        $(OPENSCAD_BIN) $(OPENSCAD_FLAGS) -D 'what="knob"' -o "$@" "$<"
 
diff --git a/another.scad b/another.scad
index fa60676..9f42f46 100644
--- a/another.scad
+++ b/another.scad
@@ -34,2 +34,7 @@ module the_extruder(
          filament_guide_d = 4,                  // PTFE filament guide diameter
+ // knob properties
+ knob_h = 10,
+ knob_bore_l = 4,
+ knob_indent_d = 4,
+ knob_indents = 12,
 
@@ -49,2 +54,3 @@ module the_extruder(
  idler_v_tolerance=.5,
+ knob_bore_d_tolerance=.6,
 
@@ -294,2 +300,30 @@ module the_extruder(
  }//body module
+
+ 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,$fn=pulley_d*PI*2);
+     translate([0,0,-1]) difference() {
+      cylinder(d=bore_d+knob_bore_d_tolerance,h=knob_bore_l+2);
+      translate([-bore_d/2-1,bore_dd-bore_d/2+knob_bore_d_tolerance/2,-1])
+      cube([bore_d+2,bore_d/2,knob_bore_l+4]);
+     }
+    }
+   }
+   difference() {
+    union() {
+     cylinder(d1=gearbox_d-2*ch,d2=gearbox_d,h=ch+epsilon,$fn=PI*gearbox_d*2);
+     translate([0,0,ch])
+     cylinder(d=gearbox_d,h=knob_h-2*ch+epsilon,$fn=PI*gearbox_d*2);
+     translate([0,0,knob_h-ch])
+     cylinder(d1=gearbox_d,d2=gearbox_d-2*ch,h=ch,$fn=PI*gearbox_d*2);
+    }
+    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=knob_indent_d*PI*2);
+   }
+  }
+ }//knob module
  
@@ -298,5 +332,7 @@ module the_extruder(
  else if(what=="body") color("yellow",0.7) body();
- else if(what=="both") {
+ else if(what=="knob") color("red",0.7) knob();
+ else if(what=="both" || what=="*") {
   color("green",0.7) lever();
   color("yellow",0.7) body();
+  color("red",0.7) knob();
  }