add SliderLeft base style

SliderLeft.scad

@@ -0,0 +1,34 @@
+M3HoleDiam = 3.4;
+
+MountSize = 40;
+
+$fn = 100;
+
+difference() {
+    MainBody();
+    M3MountHoles();
+}
+
+module M3MountHoles(){
+    edgeDistance = (MountSize-20)/2;
+
+    translate([0, edgeDistance, edgeDistance]) M3Hole(40);
+    translate([0, MountSize-edgeDistance, edgeDistance]) M3Hole(40);
+    translate([0, edgeDistance, MountSize-edgeDistance]) M3Hole(40);
+    translate([0, MountSize-edgeDistance, MountSize-edgeDistance]) M3Hole(40);
+}
+
+module M3Hole(thickness) {
+    rotate([0, 90, 0])cylinder(h = thickness, d = M3HoleDiam);
+}
+
+module MainBody() {
+    // left mount plate
+    cube([5, MountSize, MountSize]);
+
+    // bottom frame plate
+    translate([5, 0,0 ]) cube([50, MountSize, 5]);
+
+    // motorholder plate
+    translate([0, MountSize,0 ]) cube([40+5, 5, 40]);
+}