@@ -0,0 +1,47 @@
+$fn = $preview ? 12 : 180;
+tollerance=0.5;
+
+attachment_od=30;
+attachment_height=5.89;
+bayonet_od=21.5+tollerance;
+bayonet_extra=2; //radius
+bayonet_height=3.5+tollerance;
+bayonet_under=2;
+bayonet_width=7;
+
+
+module 3m_attachment() {
+    difference(){
+        cylinder(r=attachment_od/2, h=attachment_height-0.15);
+        translate([0,0,-0.1])
+        cylinder(r=bayonet_od/2, h=attachment_height+2);
+        for(i=[0:2]){
+            rotate([0,0,120*i]){
+                translate([0,0,-0.1]){
+                intersection(){
+                    cylinder(r=bayonet_od/2+bayonet_extra, h=bayonet_height+bayonet_under);
+                    translate([-bayonet_width/2, 0,0])
+                    cube([bayonet_width, attachment_od, attachment_height]);
+                }
+                intersection(){
+                    cylinder(r=bayonet_od/2+bayonet_extra, h=attachment_height);
+                    translate([0,0,bayonet_under])
+                    union(){
+                        translate([-bayonet_width/2, 0,0])
+                        cube([bayonet_width*4, attachment_od, bayonet_height]);
+                        translate([bayonet_width/2, 0,-1.2])
+                        rotate([0,-10,0])
+                        cube([bayonet_width,attachment_od,bayonet_height]);
+                    }
+                }
+                }
+            }
+        }
+    }
+}
+
+
+//To use:
+// Put in same folder as 3m_bayonet.scad and in your file: 
+//use <3m_bayonet.scad>
+3m_attachment();

@@ -0,0 +1,110 @@
+$fn = $preview ? 12 : 180;
+
+include <BOSL/constants.scad>
+use <BOSL/threading.scad>
+// https://www.thingiverse.com/thing:4246959/files by james_lan
+use <3m_bayonet.scad>
+
+// dimensions of the esp
+esp_w = 23;
+esp_d = 19+4;
+esp_h = 4;
+// horizontal spacing between the case and the esp
+esp_s = 3;
+// vertical spacing between the lid and the esp
+lid_s = 0.2;
+// vertical spacing between the case and the esp for cable management
+cable_s = 4;
+// wall thickness of the case
+wall_t = 2;
+// screw cylinder wall thickness
+screw_wall_t = 2;
+inner_screw_t = 5;
+screw_h = 16;
+screw_p = 1.5;
+//make sure that this is thicker then the diameter of a wall edge
+//assert(screw_wall_t > sqrt(2*pow(wall_t,2)), "screw wall too thin, screw may intersect with the interiour of the case");
+
+module esp_space(offset) {
+    cube([
+        esp_w + esp_s + offset*2,
+        esp_d + esp_s + offset*2,
+        esp_h + lid_s + cable_s + offset + 0.001
+    ]);
+}
+
+module case() {
+    difference() {
+        esp_space(wall_t);
+        translate([wall_t,wall_t,wall_t + 0.001])
+            esp_space(0);
+        translate([
+            -0.001,
+            (esp_d + esp_s + wall_t*2)/2 - 5,
+            wall_t + cable_s + esp_h - 3
+        ])
+        cube([
+            wall_t+0.002, 10, 3.5
+        ]);
+    }
+}
+
+a = (sqrt(2)*(screw_wall_t*2 + inner_screw_t)*0.25)-wall_t;
+module threads(offset_x, offset_y){
+    translate([offset_x,offset_y,-screw_h/2+esp_h + lid_s + cable_s + wall_t + 0.01])
+    threaded_rod(
+        d=inner_screw_t,
+        l=screw_h,
+        pitch=screw_p,
+        left_handed=false,
+        internal=true
+    );
+}
+
+module screw_cylinder(offset_x, offset_y) {
+    translate([offset_x,offset_y,0])
+        cylinder(
+            esp_h + lid_s + cable_s+wall_t,
+            d = screw_wall_t*2 + inner_screw_t
+        );
+}
+
+module 3m_bayonet(lid, offset){
+    translate([
+        (esp_w + esp_s + wall_t*2)/2,
+        (esp_d + esp_s + wall_t*2)/2,
+        offset//-7.9
+    ])
+    3m_attachment();
+}
+
+difference() {
+    union() {
+        case();
+        screw_cylinder(-a, -a);
+        //screw_cylinder(a+esp_w+esp_s+wall_t*2, -a);
+        //screw_cylinder(-a, a+esp_d+esp_s+wall_t*2);
+        screw_cylinder(a+esp_w+esp_s+wall_t*2, a+esp_d+esp_s+wall_t*2);
+    }
+    threads(-a, -a);
+    //threads(a+esp_w+esp_s+wall_t*2, -a);
+    //threads(-a, a+esp_d+esp_s+wall_t*2);
+    threads(a+esp_w+esp_s+wall_t*2, a+esp_d+esp_s+wall_t*2);
+    translate([
+        (esp_w + esp_s + wall_t*2)/2,
+        (esp_d + esp_s + wall_t*2)/2,
+        -0.001//-7.9
+    ])
+    cylinder(
+        esp_h + lid_s + cable_s+wall_t,
+        d = 26
+    );
+}
+
+translate([0,0,5])
+difference() {
+    3m_bayonet(0,-5);
+    esp_space(wall_t);
+
+}
+

@@ -0,0 +1,53 @@
+$fn = $preview ? 18 : 360;
+
+include <BOSL/constants.scad>
+use <BOSL/threading.scad>
+
+// dimensions of the esp
+esp_w = 23;
+esp_d = 19+4;
+lid_h = 0.75
+;
+// horizontal spacing between the case and the esp
+esp_s = 3;
+// wall thickness of the case
+wall_t = 2;
+// screw alignment wall thickness 
+screw_wall_t = 2;
+inner_screw_t = 5;
+//make sure that this is thicker then the diameter of a wall edge
+//assert(screw_wall_t > sqrt(2*pow(wall_t,2)), "screw wall too thin, screw may intersect with the interiour of the case");
+
+module case() {
+    module esp_space(offset) {
+        cube([
+            esp_w + esp_s + offset*2,
+            esp_d + esp_s + offset*2,
+            lid_h + offset + 0.001
+        ]);
+    }
+    esp_space(wall_t);
+}
+
+a = (sqrt(2)*(screw_wall_t*2 + inner_screw_t)*0.25)-wall_t;
+module screw_cylinder(d, h_diff, offset_x, offset_y) {
+    translate([offset_x,offset_y,-h_diff/2])
+        cylinder(
+            lid_h + wall_t+h_diff,
+            d = d
+        );
+}
+
+difference() {
+    union() {
+        case();
+        screw_cylinder(screw_wall_t*2 + inner_screw_t, 0, -a, -a);
+        //screw_cylinder(screw_wall_t*2 + inner_screw_t, 0, a+esp_w+esp_s+wall_t*2, -a);
+        //screw_cylinder(screw_wall_t*2 + inner_screw_t, 0, -a, a+esp_d+esp_s+wall_t*2);
+        screw_cylinder(screw_wall_t*2 + inner_screw_t, 0, a+esp_w+esp_s+wall_t*2, a+esp_d+esp_s+wall_t*2);
+    }
+    screw_cylinder(inner_screw_t, 0.01, -a, -a);
+    //screw_cylinder(inner_screw_t, 0.01, a+esp_w+esp_s+wall_t*2, -a);
+    //screw_cylinder(inner_screw_t, 0.01, -a, a+esp_d+esp_s+wall_t*2);
+    screw_cylinder(inner_screw_t, 0.01, a+esp_w+esp_s+wall_t*2, a+esp_d+esp_s+wall_t*2);
+}