diff --git a/helper/dovetail.scad b/helper/dovetail.scad
new file mode 100644
index 0000000..d3ff8de
--- /dev/null
+++ b/helper/dovetail.scad
@@ -0,0 +1,61 @@
+include <./common.scad>
+
+// centered on z axis
+module dovetail(
+  topWidth,
+  bottomWidth,
+  height,
+  length,
+  headExtension=0,
+  baseExtension=0,
+  frontFaceLength = 0,
+  frontFaceScale = 0,
+  backFaceLength = 0,
+  backFaceScale = 0,
+) {
+
+  translate(v=[0,0,frontFaceLength])
+  linear_extrude(length-(frontFaceLength+backFaceLength))
+  dovetailFace(topWidth,bottomWidth,height,headExtension,baseExtension);
+
+  translate(v=[0,0,frontFaceLength])
+  mirror(v=[0,0,1])
+  linear_extrude(frontFaceLength, scale=[frontFaceScale, frontFaceScale])
+  dovetailFace(topWidth,bottomWidth,height,headExtension,baseExtension);
+
+  translate(v=[0,0,length-backFaceLength])
+  linear_extrude(backFaceLength, scale=[backFaceScale,1])
+  dovetailFace(topWidth,bottomWidth,height,headExtension,baseExtension);
+
+
+
+  module dovetailFace(topWidth, bottomWidth, height, headExtension, baseExtension) {
+
+    union() {
+      // base
+      polygon(points =
+        [[-bottomWidth/2, 0],
+          [-topWidth/2, height],
+          [topWidth/2, height],
+          [bottomWidth/2, 0]]
+      );
+
+      polygon(points =
+        [[-bottomWidth/2, -baseExtension],
+          [-bottomWidth/2,0 ],
+          [bottomWidth/2, 0],
+          [bottomWidth/2, -baseExtension]]
+      );
+
+      translate(v=[0,height])
+      polygon(points =
+        [[-topWidth/2, headExtension],
+          [-topWidth/2,0 ],
+          [topWidth/2, 0],
+          [topWidth/2, headExtension]]
+      );
+    }
+  }
+
+
+}
\ No newline at end of file
diff --git a/helper/math.scad b/helper/math.scad
index dbb8953..738407b 100644
--- a/helper/math.scad
+++ b/helper/math.scad
@@ -24,6 +24,7 @@ module mirror4XY(p, dx, dy) {
     children(0);
 }
 
+// TODO: rename to simple align
 module align(a,b) {
 
     rot_axis = cross(a,b);
diff --git a/rack/print/yBar_P.scad b/rack/print/yBar_P.scad
index 7e0ad50..2a9859e 100644
--- a/rack/print/yBar_P.scad
+++ b/rack/print/yBar_P.scad
@@ -1,5 +1,11 @@
 include <../yBar.scad>
 
+include <../xBar.scad>
+
 // Oriented for 3d printing.
 // Supports required at XY wall connections, and depending on roundness
-yBar();
\ No newline at end of file
+yBar();
+
+translate(v=[140,0,0])
+rotate(a=[0,0,90])
+xBar();
\ No newline at end of file
diff --git a/rack/xBar.scad b/rack/xBar.scad
index e88f278..3d62c1c 100644
--- a/rack/xBar.scad
+++ b/rack/xBar.scad
@@ -12,6 +12,7 @@ xBarY = 32;
 xBarHeight = 15;
 
 xBarWallThickness = 2;
+xBarSideThickness = 6;
 xBarRoundness = baseRoundness;
 
 *xBar();
@@ -27,8 +28,8 @@ module xBar() {
       difference() {
         cylindricalFiletEdge(xBarY, xBarX, xBarHeight, xBarRoundness);
 
-        translate(v = [xBarWallThickness, xBarWallThickness, xBarWallThickness])
-        cylindricalFiletEdge(xBarY, xBarX-2*xBarWallThickness, xBarHeight, xBarRoundness);
+        translate(v = [xBarWallThickness, xBarSideThickness, xBarWallThickness])
+        cylindricalFiletEdge(xBarY, xBarX-2*xBarSideThickness, xBarHeight, xBarRoundness);
       }
 
       // Shave off bottom corners to reduce elephant's foot at where xBar and YBar join
@@ -47,11 +48,7 @@ module xBar() {
   }
 
   module applyYBarConnector() {
-    apply_pn() {
-
-      mirrorOtherCorner()
-      rotate(a=[0,0,-90])
-      yBarConnectorFromXLug();
+    apply_n() {
 
       mirrorOtherCorner()
       rotate(a=[0,0,-90])
diff --git a/rack/xyBarConnector.scad b/rack/xyBarConnector.scad
index ec98357..fb6d13a 100644
--- a/rack/xyBarConnector.scad
+++ b/rack/xyBarConnector.scad
@@ -1,61 +1,43 @@
 include <../helper/screws.scad>
+include <../helper/dovetail.scad>
 include <../helper/halfspace.scad>
 include <./config.scad>
 
+//xBarConnectorFromY_N();
+
 module xBarConnectorFromY_N() {
-    y1 = 6;
-    y2 = 27;
+    y = 27;
     z = 6;
-
-    slack = 0.4;
-
-    translate(v = [-m3HeatSetInsertSlotHeightSlacked, y1, z])
+    translate(v = [-m3HeatSetInsertSlotHeightSlacked, y, z])
     rotate(a = [0, 90, 0])
     heatSetInsertSlot_N(rackFrameScrewType);
 
-    translate(v = [-m3HeatSetInsertSlotHeightSlacked, y2, z])
-    rotate(a = [0, 90, 0])
-    heatSetInsertSlot_N(rackFrameScrewType);
+}
 
-    // TODO fix this up
-    // TODO need to add slack values
-    translate(v = [-1, y1+(y2-y1)/2, 0])
-    rotate(a = [0, 45, 0])
-    cube(size = [3+slack, 10+slack, 6+slack], center = true);
+module xBarConnectorFromY_P() {
+    rotate(a=[0,0,-90])
+    dovetail(topWidth = 15, bottomWidth = 12, height = 2, length = yBarHeight, headExtension = 1, baseExtension = 2, frontFaceLength = 0.5,
+    frontFaceScale = 0.90,
+    backFaceLength = 5,
+    backFaceScale = 1.2);
 }
 
 
 module yBarConnectorFromX_N() {
-    y1 = 6;
-    y2 = 27;
+    y = 27;
     z = 6;
-    slack = 0.2;
+    slack = 0.3;
 
-    translate(v = [-inf50/2, y1, z])
+
+    translate(v=[-0.5,14,0])
+    mirror(v=[1,0,0])
+    rotate(a=[0,0,-90])
+    dovetail(topWidth = 15+slack, bottomWidth = 12+slack, height = 2+slack, length = yBarHeight, headExtension = 1, baseExtension = 2, frontFaceLength = 0.5,
+    frontFaceScale = 1.1,
+    backFaceLength = 5,
+    backFaceScale = 1.2);
+
+    translate(v = [-inf50/2, y, z])
     rotate(a = [0, 90, 0])
     cylinder(r = screwRadiusSlacked(rackFrameScrewType), h = inf50, $fn = 32);
-
-    translate(v = [-inf50/2, y2, z])
-    rotate(a = [0, 90, 0])
-    cylinder(r = screwRadiusSlacked(rackFrameScrewType), h = inf50, $fn = 32);
-}
-
-// TODO: figure out nice abstraction to apply both positive and negative mods
-module yBarConnectorFromXLug() {
-    y1 = 6;
-    y2 = 27;
-    z = 6;
-
-    slack = 0.2;
-
-    intersection() {
-        // TODO fix this up, no center=true
-        translate(v = [-1, y1+(y2-y1)/2, 0])
-        rotate(a = [0, 45, 0])
-        scale(v=[0.90,0.95,0.90])
-        cube(size = [3-slack, 10-slack, 6-slack], center = true);
-
-        halfspace(vpos=[0,0,1], p=[0,0,0]);
-        halfspace(vpos=[1,0,0], p=[-2,0,0]);
-    }
 }
\ No newline at end of file
diff --git a/rack/yBar.scad b/rack/yBar.scad
index 7851716..5e1da88 100644
--- a/rack/yBar.scad
+++ b/rack/yBar.scad
@@ -15,11 +15,6 @@ include <./sharedVariables.scad>
 
 *yBar();
 
-translate(v=[20,0,0])
-*stackConnectorPlug();
-
-*stackConnectorSocket_N();
-
 module yBar() {
 
   applyBasePlateConnector()
@@ -93,7 +88,12 @@ module yBar() {
   }
 
   module applyXBarConnector() {
-    apply_n() {
+    apply_pn() {
+
+      mirrorOtherCorner()
+      translate(v=[yBarWidth + 0.5,14,0])
+      xBarConnectorFromY_P();
+
       mirrorOtherCorner()
       translate(v = [yBarWidth+eps, 0, 0])
       xBarConnectorFromY_N();