diff --git a/TODO.md b/TODO.md
new file mode 100644
index 0000000..e69de29
diff --git a/assembly.scad b/assembly.scad
index d572e60..98de3c0 100644
--- a/assembly.scad
+++ b/assembly.scad
@@ -80,4 +80,5 @@ union() {
   ysled_slider(spread=sled_ysize);
   translate([0, -1000, -1000])
   cube([2000, 2000, 2000]);
-}
\ No newline at end of file
+}
+*xsled2();
\ No newline at end of file
diff --git a/constants.scad b/constants.scad
index 3c3aac1..84444df 100644
--- a/constants.scad
+++ b/constants.scad
@@ -14,5 +14,5 @@ cur_ypos = 140;
 
 echo(str("Range = ", [ xsize - xmin * 2, ysize - ymin * 2 ]));
 
-$fs = 1.5;
+$fn = 60;
 $include_substock = true;
diff --git a/parts.scad b/parts.scad
index 384ace0..821ecb5 100644
--- a/parts.scad
+++ b/parts.scad
@@ -24,7 +24,7 @@ belt_height2 = belt_height1 + belt_width + 2;
 // calculated
 
 ysled_rail_spacing = (sled_ysize);
-motor_shaft_xoffset = (corner_size - wall_thickness) / 2;
+motor_shaft_xoffset = (corner_size - wall_thickness) / 2 + 1;
 motor_mount_length_adjustment = 4;
 motor_mount_length = nema17_face + wall_thickness + motor_mount_length_adjustment;
 
@@ -95,7 +95,9 @@ module ysled_slider(spread, associated_parts = $preview, is_left=true) {
   sled_height = frame_size;
   idler_spacing = spread / 3;
 
-  colorize("green") render() translate([ 0, -sled_len / 2, 0 ])
+  local_idler_xoffset = pulley_sbend_offset - yrail_offset + motor_shaft_xoffset;
+  echo("LIX:", local_idler_xoffset)
+  colorize("green") translate([ 0, -sled_len / 2, 0 ])
       rotate([ -90, 0, 0 ]) {
     difference() {
       union() {
@@ -107,9 +109,13 @@ module ysled_slider(spread, associated_parts = $preview, is_left=true) {
           -frame_size / 2, 0
         ]) cube([ frame_size + 5, frame_size, sled_len ]);
       }
-
-      cylinder(d = bushing_id * 1.1, h = sled_len);
-
+    
+      for (y = [idler_spacing/2, -idler_spacing/2]) {
+        rotate([90, 0, 0])
+        translate([local_idler_xoffset, sled_len/2 + y, 0])
+        cylinder(d=3, h = frame_size);
+      }
+      cylinder(d = rail_diam * 1.5, h = sled_len);
       translate([ 0, 0, -1 ]) cylinder(d = bushing_od, h = bushing_len + 1);
       translate([ 0, 0, sled_len - bushing_len ])
           cylinder(d = bushing_od, h = bushing_len + 1);
@@ -125,21 +131,20 @@ module ysled_slider(spread, associated_parts = $preview, is_left=true) {
 
   // color("#f00")
   translate(
-      [ pulley_sbend_offset - yrail_offset + motor_shaft_xoffset, 0, frame_size/2 ]) {
+      [ local_idler_xoffset, 0, frame_size/2 - 1 ]) {
     translate([ 0, idler_spacing / 2, 0 ]) {
-      idler_post(belt_height = belt_height1 - frame_size/2, toothed = is_left);
+      idler_post(belt_height = belt_height1 - frame_size/2 + 1, toothed = is_left);
     }
     translate([ 0, -idler_spacing / 2, 0 ]) {
-      *cylinder(d = 3, h = 30, $fs = 1);
-      *idler(belt_height2);
-      rotate([ 0, 0, -90 ]) { idler_post(belt_height = belt_height2 - frame_size/2, toothed = !is_left); }
+      rotate([ 0, 0, -90 ]) { idler_post(belt_height = belt_height2 - frame_size/2 + 1, toothed = !is_left); }
     }
   }
 
-  translate([ 0, -sled_len / 2, 0 ])
-      rotate([ -90, 0, 0 ]) if (associated_parts) {
-    bushing();
-    translate([ 0, 0, sled_len - bushing_len ]) bushing();
+  if ($preview) {
+    translate([ 0, -sled_len / 2, 0 ]) rotate([ -90, 0, 0 ]) 
+      bushing();
+    translate([ 0, sled_len / 2, 0 ]) rotate([ 90, 0, 0 ]) 
+      bushing();
   }
 }
 
@@ -207,11 +212,12 @@ module idler_post(belt_height, toothed = true) {
           cube([ post_radius * 2, post_radius * 2, slot_height ]);
     }
 
-    cylinder(d = 3, h = total_height + 1, $fn = 60);
+    cylinder(d = 3, h = total_height + 1, $fn = 30);
     translate([ 0, 0, total_height - 2 ]) cylinder(r = 3, h = 3);
   }
-  
-  idler(height = belt_height, toothed=toothed);
+  if($preview) {
+    idler(height = belt_height, toothed=toothed);
+  }
 }
 
 module flcorner() {
@@ -419,7 +425,7 @@ module xsled2() {
           cylinder(d = tab_thickness, h = tab_len);
           translate(
               [ -tab_thickness / 2, ysign > 0 ? -tab_thickness / 2 : 0, 0 ])
-              cube([ tab_thickness, tab_thickness / 2, tab_len ]);
+              cube([ tab_thickness, tab_thickness / 2 + 1, tab_len ]);
         }
         translate([ 0, 0, -0.5 ]) {
           cylinder(d = bushing_od, h = bushing_len + 0.5);