diff --git a/rack-mount/enclosed-box/boxHelper.scad b/rack-mount/enclosed-box/boxHelper.scad
new file mode 100644
index 0000000..3ada72e
--- /dev/null
+++ b/rack-mount/enclosed-box/boxHelper.scad
@@ -0,0 +1,53 @@
+include <../../rack/sharedVariables.scad>
+include <../common.scad>
+
+use <../sideRail.scad>
+use <../frontBoxHolder.scad>
+
+/*
+  (WIP) Enclosed box mounting system:
+  Helper file to use semi-enclosed side rails and a front plate to mount a box.
+  This system does not require any mounting holes for the enclosed box.
+
+  !!! Please also make sure that the correct rack frame preset is set in rackFrame.scad !!!
+*/
+
+// begin config ////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+boxWidth = 160;
+boxHeight = 27;
+boxDepth = 100;
+
+
+railDefaultThickness = 1.2;
+
+zOrientation = "middle";
+
+// Does not affect any part dimensions. Set this to true to visualize how a box wound be mounted.
+visualize = true;
+
+// end config //////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+#cube(size=[boxWidth, boxDepth, boxHeight]);
+
+sideSupportRailBase(top=true, defaultThickness=railDefaultThickness, supportedZ=boxHeight, supportedY=boxDepth, supportedX=boxWidth, zOrientation=zOrientation);
+
+translate(v=[boxWidth,0,0])
+mirror(v=[1,0,0])
+sideSupportRailBase(top=true, defaultThickness=railDefaultThickness, supportedZ=boxHeight, supportedY=boxDepth, supportedX=boxWidth, zOrientation=zOrientation);
+
+translate(v=[0,0,10])
+rotate(a=[-90,0,0])
+*frontBoxHolder(
+u=2,
+plateThickness=3,
+cutoutOffsetX=(rackMountScrewWidth-147)/2,
+cutoutOffsetY=4.25,
+cutoutX=147,
+cutoutY=21.5,
+support=true,
+supportedZ=boxHeight,
+supportWidth=120,
+supportDepth=5,
+supportRailBaseThickness=1.75
+);
diff --git a/rack-mount/print/sideSupportRail_P1.scad b/rack-mount/print/sideSupportRail_P1.scad
index 65c8aac..7708a6c 100644
--- a/rack-mount/print/sideSupportRail_P1.scad
+++ b/rack-mount/print/sideSupportRail_P1.scad
@@ -1,3 +1,3 @@
 use <../sideRail.scad>
 
-sideSupportRailBase(u=2, double=true, top=true, baseThickness=1.5, sideThickness=4, backThickness=2, supportedZ=27.2, supportedY=101.5, supportedX=159);
\ No newline at end of file
+sideSupportRailBase(top=true, defaultThickness=1.4, supportedZ=27.2, supportedY=101.5, supportedX=159);
\ No newline at end of file
diff --git a/rack-mount/print/sideSupportRail_P2.scad b/rack-mount/print/sideSupportRail_P2.scad
index 366ab2d..3236205 100644
--- a/rack-mount/print/sideSupportRail_P2.scad
+++ b/rack-mount/print/sideSupportRail_P2.scad
@@ -1,4 +1,4 @@
 use <../sideRail.scad>
 
 mirror(v=[1,0,0])
-sideSupportRailBase(u=2, double=true, top=true, baseThickness=1.5, sideThickness=4, backThickness=2, supportedZ=27.2, supportedY=101.5, supportedX=159);
\ No newline at end of file
+sideSupportRailBase(top=true, defaultThickness=1.4, supportedZ=27.2, supportedY=101.5, supportedX=159);
\ No newline at end of file
diff --git a/rack-mount/print/tray_P.scad b/rack-mount/print/tray_P.scad
index 3e4adee..34b3327 100644
--- a/rack-mount/print/tray_P.scad
+++ b/rack-mount/print/tray_P.scad
@@ -1,7 +1,7 @@
 use <../tray.scad>
 
 /*
-  Parametric rack-mount tray -
+  Parametric rack-mount tray:
   Dimensions can be adjusted using the variables below. You can also add mounting holes to fasten things that have
   screw holes at the bottom.
 
diff --git a/rack-mount/sideRail.scad b/rack-mount/sideRail.scad
index 4dd2416..1feeb5c 100644
--- a/rack-mount/sideRail.scad
+++ b/rack-mount/sideRail.scad
@@ -3,115 +3,144 @@ include <../config/common.scad>
 include <../rack/sharedVariables.scad>
 include <./common.scad>
 
-sideSupportRailBase(u=2, double=true, top=true, baseThickness=1.5, sideThickness=4, backThickness=2, supportedZ=27.2, supportedY=101.5, supportedX=159);
+//sideSupportRailBase(top=true, defaultThickness=1.5, supportedZ=27.2, supportedY=101.5, supportedX=159);
 
 // distance between front and back main rail screw mounts
 sideRailScrewMountDist = yBarDepth - 2*(frontScrewSpacing + railFrontThickness + railSlotToXZ);
 
-module sideSupportRailBase(u=2, double=true, top=true, baseThickness=2, sideThickness=2, backThickness=2, supportedZ=27.5, supportedY=101.5, supportedX=159) {
+module sideSupportRailBase(top=true, supportedZ, supportedY, supportedX, zOrientation="middle", defaultThickness=2) {
 
-  // TODO simplify this
   mountBlockHeight = 10;
   mountBlockDepth = 10;
   screwMountGlobalDz = screwDiff / 2.0; // vertical distance between local origin and main rail screw mount
   sideRailScrewToMainRailFrontDx = frontScrewSpacing+railFrontThickness;
-  railLength = max(sideRailScrewMountDist + sideRailScrewToMainRailFrontDx + mountBlockDepth/2, supportedY+backThickness);
-  railBaseThickness = baseThickness;
-  railSideThickness = sideThickness;
+  railLength = max(sideRailScrewMountDist + sideRailScrewToMainRailFrontDx + mountBlockDepth/2, supportedY+defaultThickness);
+  railBaseThickness = defaultThickness; // default thickness value
+  railSideThickness = 4;
+  railBackThickness = 3;
   railBaseWidth = 15;
-  railSideHeight = supportedZ + railBaseThickness*2 + overhangSlack;
+  // Minimum U to enclose box, while also have a minimum defaultThickness for top and bottom.
+  minU = max(1, ceil((supportedZ + 2*railBaseThickness) / uDiff)-1);
 
+  railBottomThickness =
+    (zOrientation == "middle")
+    ? (((minU+1) * uDiff) - supportedZ)/2
+    : (zOrientation == "bottom")
+    ? railBaseThickness
+    : railBaseThickness;
+
+  assert(supportedX <= maxUnitWidth);
+  assert (zOrientation == "middle" || zOrientation == "bottom", "Z-Orientation not supported");
+  assert(railBottomThickness >= railBaseThickness);
+
+  railSideHeight = supportedZ + railBaseThickness + railBottomThickness + overhangSlack;
   frontMountPad = (sideRailScrewToMainRailFrontDx-mountBlockDepth/2)-xySlack;
 
+  translate(v=[-railSideThickness, 0, -railBottomThickness])
   applyMainRailMounts()
   sideSupportRailBase();
 
-  echo(frontScrewSpacing);
-  echo(sideRailScrewToMainRailFrontDx);
-
   module applyMainRailMounts() {
-    mountBlockExtension = (railSupportsDx - supportedX)/2 - railSideThickness;
-    assert(mountBlockExtension >= 10);
 
-    apply_p() {
-      union() {
-        translate(v = [0, frontMountPad, 0])
-        mountBlockColumn(mountBlockExtension=mountBlockExtension, u=u);
-        translate(v=[0,frontMountPad+sideRailScrewMountDist, 0])
-        mountBlockColumn(mountBlockExtension=mountBlockExtension, u=u);
-      }
+    mountBlockExtension = (railSupportsDx - supportedX)/2 - railSideThickness;
+    minHexNutPocketToXYDist = mountBlockHeight/2;
+    minHexNutPocketToXZDist = mountBlockDepth/2;
+    minHexNutPocketToYZDist = 4;
+    screwU = floor((railSideHeight) / uDiff)-1;
+
+    apply_pn() {
+      mountBlockPositive();
+      mountBlockNegative();
       children(0);
     }
-  }
 
-  module mountBlockColumn(mountBlockExtension, u) {
+    module mountBlockPositive() {
+      translate(v = [0, frontMountPad, 0])
+        singleMountBlockPositive();
+      translate(v=[0,frontMountPad+sideRailScrewMountDist, 0])
+        singleMountBlockPositive();
+    }
 
-    difference() {
+    module mountBlockNegative() {
+      translate(v = [0, frontMountPad, 0])
+        singleMountBlockNegative();
+      translate(v=[0,frontMountPad+sideRailScrewMountDist, 0])
+        singleMountBlockNegative();
+    }
+
+    module singleMountBlockPositive() {
       translate(v = [-mountBlockExtension, 0, 0])
-      cube(size = [mountBlockExtension, mountBlockDepth, railSideHeight]);
+        cube(size = [mountBlockExtension, mountBlockDepth, railSideHeight]);
+    }
 
-      union() {
+    module singleMountBlockNegative() {
+      nutPocket();
+
+      translate(v = [0, 0, uDiff*screwU])
         nutPocket();
 
-        if (double) {
-          translate(v=[0,0,uDiff * u]) // screwMountToGlobalZ
-          nutPocket();
-        }
-
+      module nutPocket() {
+        translate(v=[-mountBlockExtension+minHexNutPocketToYZDist, minHexNutPocketToXZDist, minHexNutPocketToXYDist])
+        rotate(a=[-90,0,90])
+          hexNutPocket_N(rackFrameScrewType, openSide=false, backSpace=min((railSideThickness-1)+mountBlockExtension-minHexNutPocketToYZDist,15));
       }
     }
-
-    module nutPocket() {
-      translate(v=[-mountBlockExtension/2,mountBlockDepth/2,mountBlockHeight/2]) // screwMountToGlobalZ
-      rotate(a=[90,0,0])
-      rotate(a=[0,90,0])
-      hexNutPocket_N(rackFrameScrewType, openSide=false);
-    }
-
   }
 
+
   module sideSupportRailBase() {
-    backThickness = 3;
 
     difference () {
       union() {
-        cube(size = [railBaseWidth, railLength, railBaseThickness]);
+        cube(size = [railBaseWidth, railLength, railBottomThickness]);
 
         cube(size = [railSideThickness, railLength, railSideHeight]);
 
         // back support
-        translate(v = [0, max(railLength-backThickness, supportedY), 0])
-        cube(size = [railBaseWidth, backThickness, railSideHeight]);
+        translate(v = [0, max(railLength-railBackThickness, supportedY), 0])
+        cube(size = [railBaseWidth, railBackThickness, railSideHeight]);
 
         // back support for box
         translate(v = [0, supportedY, 0])
-        cube(size = [railBaseWidth, backThickness, railSideHeight]);
+        cube(size = [railBaseWidth, railBackThickness, railSideHeight]);
 
         // top support
         if (top) {
-          translate(v = [0, 0, railSideHeight-baseThickness])
+          translate(v = [0, 0, railSideHeight-railBaseThickness])
           cube(size = [railBaseWidth, railLength, railBaseThickness]);
         }
-
       }
+
       union() {
         distanceFromSeparator = 3;
-        r = 5;
+        r = 4;
 
-        boxDy = frontMountPad+r+mountBlockDepth+distanceFromSeparator;
-        boxDz = baseThickness+distanceFromSeparator+r;
-        translate(v=[0,boxDy,boxDz])
-        minkowski() {
-          cube(size = [sideThickness, supportedY-(boxDy+distanceFromSeparator+r), railSideHeight-2*boxDz]);
-          sphere(r=r);
-        }
-        translate(v=[0,supportedY+distanceFromSeparator+r+backThickness,boxDz])
-        minkowski() {
-          cube(size = [sideThickness, 25, railSideHeight-2*boxDz]);
-          sphere(r=r);
+        ventDy1 = frontMountPad+mountBlockDepth+distanceFromSeparator;
+        ventY1 = min(supportedY-(ventDy1+distanceFromSeparator), sideRailScrewMountDist-(2*distanceFromSeparator+mountBlockDepth));
+
+        ventDy2 = max(ventDy1, supportedY+railBackThickness+distanceFromSeparator);
+        ventY2 = max(0, railLength - (ventDy2 + distanceFromSeparator + mountBlockDepth));
+
+        ventDz = railBottomThickness+distanceFromSeparator+r;
+        ventZ = railSideHeight-(ventDz+distanceFromSeparator+r+railBaseThickness);
+
+        if (ventY1 > 2*r) {
+          translate(v = [0, ventDy1+r, ventDz])
+            minkowski() {
+              cube(size = [inf, ventY1-2*r, ventZ]);
+              sphere(r = r);
+            }
         }
 
-        cylindricalFiletNegative(p0=[railBaseWidth,0,0],p1=[railBaseWidth,0,inf], n=[1,-1,0],r=4);
+        if (ventY2 > 2*r) {
+          translate(v = [0, ventDy2+r, ventDz])
+            minkowski() {
+              cube(size = [inf, ventY2-2*r, ventZ]);
+              sphere(r = r);
+            }
+        }
+
+        cylindricalFiletNegative(p0=[railBaseWidth,0,0],p1=[railBaseWidth,0,inf], n=[1,-1,0],r=r);
       }
     }
   }