diff --git a/ino/components/mcopy_capper/mcopy_capper.ino b/ino/components/mcopy_capper/mcopy_capper.ino
index 0106e9f..bcbdf15 100644
--- a/ino/components/mcopy_capper/mcopy_capper.ino
+++ b/ino/components/mcopy_capper/mcopy_capper.ino
@@ -49,7 +49,7 @@ const int serialDelay = 5;
 Servo servo;
 //SG-5010 speed 0.18s / 60 degree
 //converted to milliseconds/angle
-const float servoSpeed = 200.0 / 60.0;
+const float servoSpeed = 400.0 / 60.0;
 
 void setup() {
   Serial.begin(57600);
diff --git a/scad/capper.scad b/scad/capper.scad
index a421ec1..6bc6bec 100644
--- a/scad/capper.scad
+++ b/scad/capper.scad
@@ -5,9 +5,11 @@ include <common.scad>;
 // https://www.thingiverse.com/thing:83806 - Lego mount (has dimensions of servo body)
 // https://www.thingiverse.com/thing:5241574 - Robot arm (just cool)
 
+currentAngle=-60;
+
 LensVoidDiameter = 40; //mm
 LensZ = 80;
-LensY = 20;
+LensY = 30;
 
 CapOffsetX = -50;
 CapOffsetY = -11;
@@ -16,35 +18,59 @@ CapWidthZ = 4;
 
 BoltSpacingX = 10;
 BoltSpacingY = 49;
-BoltD = 5;
+BoltD = 3.5;
+
+RailSlotsX = 20;
+RailSlotsD = 6;
+
+MountBoltSpacingY=40;
+
+OptoEndstopAdjustZ=0.25;
+
+module BoltVoid () {
+    cylinder(r=R(BoltD), h=20, center=true);
+    translate([0, 0, 4]) m3_nut(5);
+}
 
 module Mount () {
 	$fn = 200;
 	difference(){
         union(){
-            difference(){
+            translate([0, 0, 5]) difference(){
                 cylinder(r=R(LensVoidDiameter)+15, h=LensY, center=true);
                 cylinder(r=R(LensVoidDiameter)+5, h=LensY+1, center=true);
             }
             translate([0,0,-(LensY/4)-(5/4)]) difference(){
-                cylinder(r=R(LensVoidDiameter)+5, h=R(LensY)-R(5), center=true);
+                cylinder(r=R(LensVoidDiameter)+5, h=R(LensY)-R(5)-10, center=true);
                 cylinder(r=R(LensVoidDiameter), h=LensY+1, center=true);
             }
             difference () {
-                translate([50, 0, -6]) cube([100, LensVoidDiameter + 30, 8], center=true);
+                union() {
+                    translate([50, 0, -6]) cube([100, LensVoidDiameter + 30, 8], center=true);
+                    translate([0, 0, -6]) cylinder(r=R(LensVoidDiameter)+12, h=8, center=true);
+                }
                 cylinder(r=R(LensVoidDiameter), h=LensY+1, center=true);
+                //servo
                 translate([50, 0, -6]) {
                     cube([20, 40.25, 10], center = true);
-                    translate([BoltSpacingX/2, BoltSpacingY/2, 0])cylinder(r=R(BoltD), h=20, center=true);
-                    translate([-BoltSpacingX/2, BoltSpacingY/2, 0])cylinder(r=R(BoltD), h=20, center=true);
-                    translate([BoltSpacingX/2, -BoltSpacingY/2, 0])cylinder(r=R(BoltD), h=20, center=true);
-                    translate([-BoltSpacingX/2, -BoltSpacingY/2, 0])cylinder(r=R(BoltD), h=20, center=true);
+                    translate([BoltSpacingX/2, BoltSpacingY/2, 0]) BoltVoid();
+                    translate([-BoltSpacingX/2, BoltSpacingY/2, 0]) BoltVoid();
+                    translate([BoltSpacingX/2, -BoltSpacingY/2, 0]) BoltVoid();
+                    translate([-BoltSpacingX/2, -BoltSpacingY/2, 0]) BoltVoid();
                 }
+                translate([50, 0, -6-3.01]) cube([2, 56, 2], center=true);
             }
         }
-		translate([0,R(LensVoidDiameter),0])cube([LensVoidDiameter*2, LensVoidDiameter, 5], center=true);
+		translate([0,R(LensVoidDiameter),1+7.5]) cube([LensVoidDiameter*2, LensVoidDiameter, 7], center=true);
+        //
+        translate([80, R(MountBoltSpacingY), 0]) RailSlots();
+        translate([80, -R(MountBoltSpacingY), 0]) RailSlots();
+        //endstop
+        translate([0, -34, 25-2-2]) {
+            cube([14, 20, 50], center=true);
+            translate([0, 11, -12.5]) cylinder(r=R(22), h=4, center=true);
+        }
 	}
-    
 }
 
 module Cap () {
@@ -66,21 +92,106 @@ module Cap () {
             }
             translate([0, 0, -4]) cylinder(r=5,h=4,center=true);
         }
-        translate([0, 0, -4]) cylinder(r1=R(5.5), r2=R(5.4),h=4.01,center=true);
-        cylinder(r=R(5.4),h=10,center=true);
+        translate([0, 0, -4]) cylinder(r1=R(5.85), r2=R(5.5), h=4.01,center=true, $fn=20);
+        cylinder(r=R(2.5), h=10,center=true);
+        translate([0, 0, 2.5]) cylinder(r=R(7.5), h=5,center=true);
     }
-}
-module Debug () {
-    Mount();
-    translate([-CapOffsetX,-CapOffsetY,0]) rotate([0,0,-60]) Cap();
+    translate([CapOffsetX,CapOffsetY - R(LensVoidDiameter) - 4, 1.25]) cylinder(r=R(15), h=1.5, center=true);
 }
 
-Render="Debug";
+module MountFront () {
+    $fn=60;
+    difference () {
+        Mount();    
+        translate([0, -50, 50-2]) cube([100, 100, 100], center=true);
+        translate([0, 0, 50-2+7]) cube([100, 100, 100], center=true);
+        translate([0,-30,-2]) cylinder(r=R(4), h=3, center=true);
+        rotate([0,0,40]) translate([0,-30,-2]) cylinder(r=R(4), h=3, center=true);
+        rotate([0,0,-40])translate([0,-30,-2]) cylinder(r=R(4), h=3, center=true);
+        rotate([0,0,80]) translate([0,-30,-2]) cylinder(r=R(4), h=3, center=true);
+        rotate([0,0,-80])translate([0,-30,-2]) cylinder(r=R(4), h=3, center=true);
+        translate([90, 0, -11]) rotate([45,0,0]) cube([70, 4.3, 4.3], center=true);
+    }   
+}
+
+module MountBack () {
+    $fn=60;
+    difference () {
+        Mount();
+        translate([0, 0, -50-1.999]) cube([400, 100, 100], center=true);
+        translate([0, 50, -50+2+7]) cube([100, 100, 100], center=true);
+    }
+    //translate([0,-30,-2]) cylinder(r=R(3.9), h=3, center=true);
+    rotate([0,0,40]) translate([0,-30,-2]) cylinder(r=R(3.9), h=3, center=true);
+    rotate([0,0,-40])translate([0,-30,-2]) cylinder(r=R(3.9), h=3, center=true);
+    rotate([0,0,80]) translate([0,-30,-2]) cylinder(r=R(3.9), h=3, center=true);
+    rotate([0,0,-80])translate([0,-30,-2]) cylinder(r=R(3.9), h=3, center=true);
+}
+
+module RailSlots () {
+    translate([R(RailSlotsX), 0, 0]) cylinder(r=R(RailSlotsD), h=40, center=true);
+    translate([-R(RailSlotsX), 0, 0]) cylinder(r=R(RailSlotsD), h=40, center=true);
+    cube([RailSlotsX, RailSlotsD, 40], center=true);
+}
+
+module RailMount () {
+    //
+    X=110;
+    RailD=15;
+    RailSpacingY=80;
+    $fn=60;
+    difference () {
+        translate([X, 0, -14]) difference () {
+            cube([100, LensVoidDiameter + 30.6, 8], center=true);
+            //
+            translate([-40, R(MountBoltSpacingY), 0]) cylinder(r=R(6),h=40,center=true);
+            translate([-40, -R(MountBoltSpacingY), 0]) cylinder(r=R(6),h=40,center=true);
+        }
+        
+    }
+    translate([X, 0, -11]) rotate([45,0,0]) cube([100, 4, 4], center=true);
+    translate([X + R(100), 0, -14]) cube([8, LensVoidDiameter + 30.6, 28], center=true);
+    translate([X + R(100) + 5 ,R(RailSpacingY),-14]) difference() {
+        translate([-2.5, -2.5, 0]) cylinder(r=R(RailD + 5), h=28, center=true);
+        cylinder(r=R(RailD), h=28+1, center=true);
+    }
+}
+
+module OptoEndstopMount () {
+        translate([-5,9.5,20]) {
+            difference() {
+                cube([14-0.3, 14, 24], center=true);
+                translate([0, R(LensVoidDiameter)+15+4, 0]) cylinder(r=R(LensVoidDiameter)+15, h=LensY, center=true, $fn=200);
+                translate([0,-8.3,0]) cube([7.25, 8, 24+1], center=true);
+                translate([0,-5,-9+OptoEndstopAdjustZ]) rotate([90, 0, 0]) cylinder(r=R(2.9),h=10,center=true, $fn=40);
+                translate([0,-5,10+OptoEndstopAdjustZ]) rotate([90, 0, 0]) cylinder(r=R(2.9),h=10,center=true, $fn=40);
+                translate([0,1,1+OptoEndstopAdjustZ]) cube([8,14,11.5],center=true);
+                translate([0,6,.75+OptoEndstopAdjustZ]) cylinder(r=R(22), h=4, center=true);
+            }
+            
+        }
+}
+
+module Debug () {
+    Mount();
+    translate([-CapOffsetX,-CapOffsetY,6.11 + 1.9]) rotate([0,0,currentAngle]) Cap();
+    //color("green") RailMount();
+    translate([5, -38, -11.8+OptoEndstopAdjustZ]) rotate([0, -90, 0]) opto_endstop();
+    translate([5, -38, -11.8]) OptoEndstopMount();
+}
+
+Render="OptoEndstopMount";
 
 if (Render=="Debug") {
     Debug();
 } else if (Render=="Cap") {
     Cap();
-} else if (Render=="Mount") {
-    Mount();    
+} else if (Render=="MountFront") {
+    MountFront();    
+} else if (Render=="MountBack") {
+    MountBack();
+} else if (Render=="RailMount") {
+    RailMount();
+} else if (Render=="OptoEndstopMount") {
+    rotate([-90,0,0]) OptoEndstopMount();    
 }
\ No newline at end of file
diff --git a/scad/common.scad b/scad/common.scad
index 48417a4..2719a7e 100644
--- a/scad/common.scad
+++ b/scad/common.scad
@@ -32,4 +32,43 @@ module trap_cube(height = 19, top_x = 30, top_y = 34, bottom_x = 45, bottom_y =
 }
 
 echo("common.scad - R()");
-function R (diameter) = diameter / 2.0;
\ No newline at end of file
+function R (diameter) = diameter / 2.0;
+
+echo("common.scad - m3_nut");
+module m3_nut (H = 5) {
+    cylinder(r=R(6.6), h=H, center=true, $fn=6);
+}
+
+module opto_endstop(){
+ difference(){
+  union(){
+  // base PCB
+   color("green") cube([33.0,1.6,10.5]);
+  // add the switch module
+   translate([8.4,1.6,10.5/2-6.4/2]) optoswitch();
+   // connector
+   translate([0.2,-7,0]) color("white") cube([5.8,7,10.5]);
+   // led
+   translate([3.5,1.6,10.5/2-1.5/2]) color("red") cube([2,0.7,1.5]);
+  }
+   translate([8.4,0,10.5/2-6.4/2]) {
+   for ( hole = [2.75,24.5-2.75] ){
+    rotate([90,0,0]) translate([hole,6.4/2,-4]) cylinder(r=1.5, h=4.5,$fn=40);
+   }
+  }
+ }
+}
+
+// switch module
+module optoswitch() {
+    difference(){
+        union (){
+            color("gray") cube([24.5,3.5,6.4]);
+            color("gray")translate([6.63,0,0]) cube([4.45,11.3,6.3]);
+            color("gray")translate([13.63,0,0]) cube([4.45,11.3,6.3]);
+        }
+       for ( hole = [2.75,24.5-2.75] ){
+           rotate([90,0,0]) translate([hole,6.4/2,-4]) cylinder(r=1.5, h=4.5,$fn=40);
+       }	
+     }
+ }
\ No newline at end of file
diff --git a/stl/capper_cap.stl b/stl/capper_cap.stl
index 54cdacb..64cd675 100644
Binary files a/stl/capper_cap.stl and b/stl/capper_cap.stl differ
diff --git a/stl/capper_mount_back.stl b/stl/capper_mount_back.stl
new file mode 100644
index 0000000..91f3403
Binary files /dev/null and b/stl/capper_mount_back.stl differ
diff --git a/stl/capper_mount_front.stl b/stl/capper_mount_front.stl
new file mode 100644
index 0000000..b2a3ff3
Binary files /dev/null and b/stl/capper_mount_front.stl differ
diff --git a/stl/capper_opto.stl b/stl/capper_opto.stl
new file mode 100644
index 0000000..9c985f7
Binary files /dev/null and b/stl/capper_opto.stl differ