diff --git a/bobbin.scad b/bobbin.scad
new file mode 100644
index 0000000..97253d2
--- /dev/null
+++ b/bobbin.scad
@@ -0,0 +1,47 @@
+difference() {
+    union() {
+        // base object
+        cube([40, 28, 1]){}
+            
+        // four corner nubbins
+        translate([5, 0, 0]){
+            cylinder(1, 5, 5){}
+        }
+        translate([5, 28, 0]){
+            cylinder(1, 5, 5){}
+        }
+        translate([35, 0, 0]){
+            cylinder(1, 5, 5){}
+        }
+        translate([35, 28, 0]){
+            cylinder(1, 5, 5){}
+        }
+    }
+
+    // ring hook hole
+    translate([5.5, 14, -1]){
+        cylinder(3, 4, 4){}
+    }
+    
+    // thread catchers
+    translate([0, 2, -1]) {
+        rotate([0, 0, 35]){
+            cube([10, .25, 3]){}
+        }
+    }
+    translate([8.25, 20, -1]) {
+        rotate([0, 0, 145]){
+            cube([10, .25, 3]){}
+        }
+    }
+    translate([40.25, 2, -1]) {
+        rotate([0, 0, 145]){
+            cube([10, .25, 3]){}
+        }
+    }
+    translate([32.25, 20, -1]) {
+        rotate([0, 0, 35]){
+            cube([10, .25, 3]){}
+        }
+    }
+}