diff --git a/README.md b/README.md
index 6618049..85d147d 100644
--- a/README.md
+++ b/README.md
@@ -2319,7 +2319,21 @@ This area covers specific build notes for specific cases.  Hardware used or othe
 The panel_nas design can be CNC cut or 3D printed.  By changing the top and bottom standoff type to "none" in the *SBC Standoff Global Settings* tabs respectively, only a hole is generated for CNC cutting support.  Panels can be exported in DXF or SVG by selecting the *part" view under the *view* tab, then the indivual part and select the *section part* checkbox. After the projection has been generated render it by pressing F7 or by selecting render from the user interface.  Exported DXF and SVG file formats are available under the File->Export menu.
 
 ### rack Case Design
-This case is divided into 3 pieces for the 19" cases and 2 pieces for the 10" cases.  They can be selected in the *part* view for STL export under the *view* tab by selecting the left, bottom or right individual part.  The peices are held together using M2x8mm screws and nuts.  The 10 inch cases requires 5 sets of screws and nuts and the 19" rack case takes 10 sets. 
+This case is divided into 3 pieces for the 19" cases and 2 pieces for the 10" cases.  They can be selected in the *part* view for STL export under the *view* tab by selecting the left, bottom or right individual part.  The peices are held together using M2x8mm screws and nuts.
+
+10” rack case Qty 5 - M2x8mm screws cap or countersunk with nuts.
+19” rack case Qty 10 - M2x8mm screws cap or countersunk with nuts.
+Appropriate fasteners for all SBC.
+
+For a better fit, prep the edges of the case pieces prior to assembly.  Use sand paper or a file to remove any imperfections and true the edge.
+
+Using 2mm thickness for the floor and walls provides for an adequate case in most enclosed applications but a 3mm floor  or better is recommended for removable and open front cases.
+
+There are 3mm holes on the left, center and right, both front and rear, to use for feet when deployed as a single bench top case.  If using the rack stands, the holes can be used to mount an external standoff to support the rear of a heavy case.
+
+All case bodies can be printed without the use of support.  Only the removable bay tray needs support for printing.  SBC placement so as to bisect a SBC opening with a case divide, will require print supports.
+
+Varies accessories (1u rack stand, grommets, fan covers, 2.5” drive holder, washers, etc) are available from sbccb_accessory_tool.scad.  The table top rack stand is comprised of two interchangeable brackets that can hold 1U-4U rack cases.
 
 
 ## Accuracy
diff --git a/lib/fastener.scad b/lib/fastener.scad
index 354a9f4..e3dd2a5 100644
--- a/lib/fastener.scad
+++ b/lib/fastener.scad
@@ -21,20 +21,20 @@
 
 
 /*
-           NAME: fan_cover
-    DESCRIPTION: creates fan covers for fan openings
+           NAME: m_insert
+    DESCRIPTION: creates brass inserts for models
            TODO: none
 
-          USAGE: m_insert(type="M3", icolor = "#ebdc8b")
+          USAGE: m_insert(type="m3", icolor = "#ebdc8b")
 
-                           type = "M3"
+                           type = "m3"
                          icolor = color of insert
 */
 
-module m_insert(type="M3", icolor = "#ebdc8b") {    //#f4e6c3, #ebdc8b 
+module m_insert(type="m3", icolor = "#ebdc8b") {    //#f4e6c3, #ebdc8b 
     
-    odiam = type == "M3" ? 4.2 : 3.5;
-    idiam = type == "M3" ? 3 : 2.5;
+    odiam = type == "m3" ? 4.2 : 3.5;
+    idiam = type == "m3" ? 3 : 2.5;
     iheight = 4;
 
     difference() {
@@ -46,3 +46,36 @@ module m_insert(type="M3", icolor = "#ebdc8b") {    //#f4e6c3, #ebdc8b
             cube([.5, .5, 1.5]);
     }
 }
+
+
+/*
+           NAME: washer
+    DESCRIPTION: creates washers
+           TODO: none
+
+          USAGE: washer(type="round", id=3, od=6, iheight=2, sheight=2, countersunk, icolor = "#ebdc8b")
+
+                        type = "round", "shouldered"
+                          id = inside diameter
+                          od = outside diameter
+                     iheight = washer thickness
+                     sheight = shoulder height
+                 countersunk = true
+                      icolor = color of washer
+*/
+
+module washer(type="round", id=3, od=6, iheight=2, sheight=2, countersunk = false, icolor = "#ebdc8b") {    //#f4e6c3, #ebdc8b 
+    
+    difference() {
+        union() {
+            color(icolor,.6) cylinder(d=od, h=iheight);
+            if(type == "shouldered") {
+                color(icolor,.6) cylinder(d=od+4, h=sheight);
+            }
+        }
+        color(icolor,.6) translate([0,0,-1]) cylinder(d=id, h=od+sheight+2);
+        if(type == "shouldered" && countersunk == true) {
+            color(icolor,.6) translate([0,0,-.01]) cylinder(d2=id, d1=6, h=sheight);
+        }
+    }
+}
diff --git a/mod/case_rack.scad b/mod/case_rack.scad
index 38fbb22..7013d74 100644
--- a/mod/case_rack.scad
+++ b/mod/case_rack.scad
@@ -723,7 +723,16 @@ if(case_design == "rack" && side == "bottom") {
             slab([width-(2*wallthick),depth-(2*wallthick),2+adj],corner_fillet);
         translate([-gap-wallthick-adj,-gap-wallthick,case_z-floorthick]) 
             slab([width,depth+adj,20],corner_fillet);
+
+        // case exterior support holes
+        translate([-gap-wallthick+10,depth-2*(wallthick+gap)-5,-adj]) cylinder(d=3, h=floorthick+(2*adj));
+        translate([450/2-gap-wallthick,depth-2*(wallthick+gap)-5,-adj]) cylinder(d=3, h=floorthick+(2*adj));
+        translate([450-gap-wallthick-10,depth-2*(wallthick+gap)-5,-adj]) cylinder(d=3, h=floorthick+(2*adj));
+        translate([-gap-wallthick+10,5,-adj]) cylinder(d=3, h=floorthick+(2*adj));
+        translate([450/2-gap-wallthick,5,-adj]) cylinder(d=3, h=floorthick+(2*adj));
+        translate([450-gap-wallthick-10,5,-adj]) cylinder(d=3, h=floorthick+(2*adj));
     }
+
     // additive accessories
     if(accessory_name != "none") {
         for (i=[1:11:len(accessory_data[a[0]])-1]) {
diff --git a/sbccb_accessory_tool.scad b/sbccb_accessory_tool.scad
index a847e2e..601612e 100644
--- a/sbccb_accessory_tool.scad
+++ b/sbccb_accessory_tool.scad
@@ -26,9 +26,18 @@
     individual_part = "bottom"; // [top, bottom, right, left, front, rear, io_shield, accessories]
     // section individual parts for panel cases
     section_part = false; // [true,false]
-    accessory = "grommet"; // ["fan cover", "grommet", "hd25 holder", "1u rack stand"]
+    accessory = "grommet"; // ["1u rack stand", "2.5 drive holder", "fan cover", "grommet", "washer"]
 
-    /* [Fan Cover] */
+    /* [1U Rack Stand] */
+    rack_width = 19; // [10, 19]
+    rack_1u = 4; // [1 : 4]
+    rack_fasteners = "nut"; // ["none", "nut", "insert"]
+
+    /* [2.5" Drive Holder] */
+    holder_length = 110; // [110, 145]
+    holder_width = 101.6; // [101.6 : .1 : 150]
+
+   /* [Fan Cover] */
     fan_style = "fan_hex"; // ["fan_open", "fan_1", "fan_2", "fan_hex"]
     fan_size = 40; // [25, 30, 40, 50, 60, 80, 92, 120]
     fan_cover_thickness = 2; // [2 : .25 : 5]
@@ -39,14 +48,13 @@
     grommet_id = 6; // [2 : .25 : 20]
     installation_wall_thickness = 2; // [2 : .25 : 5]
 
-    /* [2.5" HD Holder] */
-    holder_length = 110; // [110, 145]
-    holder_width = 101.6; // [101.6 : .1 : 150]
-
-    /* [1U Rack Stand] */
-    rack_width = 19; // [10, 19]
-    rack_1u = 4; // [1 : 4]
-    rack_fasteners = "nut"; // ["none", "nut", "insert"]
+    /* [Washer] */
+    washer_style = "flat"; // ["flat", "shouldered"]
+    washer_od = 5; // [3 : .25 : 20]
+    washer_id = 3; // [2 : .25 : 20]
+    washer_thickness = 2; // [1 : .25 : 8]
+    shoulder_height = 3; // [1 : .25 : 4]
+    shoulder_countersunk = false; // [true,false]
 
     /* [Hidden] */
     mask = [true, 10, 2, "default"];
@@ -58,23 +66,32 @@
 
     // model view
     if (view == "model") {    
+        if(accessory == "1u rack stand") {
+            rack_stand(rack_1u);
+        }
+        if(accessory == "2.5 drive holder") {
+            hd35_25holder(holder_length, holder_width);
+        }
         if(accessory == "fan cover") {
             fan_cover(fan_size, fan_cover_thickness, fan_style);
         }
         if(accessory == "grommet") {
             grommet("front", grommet_style, grommet_od, grommet_id, installation_wall_thickness, true, nmask);
         }
-        if(accessory == "hd25 holder") {
-            hd35_25holder(holder_length, holder_width);
-        }
-        if(accessory == "1u rack stand") {
-            rack_stand(rack_1u);
+        if(accessory == "washer") {
+            washer(washer_style, washer_id, washer_od, washer_thickness, shoulder_height, shoulder_countersunk, "silver");;
         }
     }
 
 
     // platter view
     if (view == "platter") {
+        if(accessory == "1u rack stand") {
+            rotate([0,270,0]) rack_stand(rack_1u);
+        }
+        if(accessory == "2.5 drive holder") {
+            hd35_25holder(holder_length, holder_width);
+        }
         if(accessory == "fan cover") {
             fan_cover(fan_size, fan_cover_thickness, fan_style);
         }
@@ -90,10 +107,8 @@
             translate([0,-20,0])
                 grommet_clip(grommet_style, grommet_od, grommet_id, installation_wall_thickness);
         }
-        if(accessory == "hd25 holder") {
-            hd35_25holder(holder_length, holder_width);
-        }
-        if(accessory == "1u rack stand") {
-            rotate([0,270,0]) rack_stand(rack_1u);
+        if(accessory == "washer") {
+            washer(washer_style, washer_id, washer_od, washer_thickness, 
+                shoulder_height, shoulder_countersunk, "silver");
         }
     }