add wip side mount l-bracket. also update mainRail with flush screws

rack-mount/side-rail/dualMount.scad

@@ -0,0 +1,91 @@
+include <../../helper/common.scad>
+include <../../helper/math.scad>
+include <../../helper/screws.scad>
+include <../../rack/config.scad>
+
+sideSupportRailBase("lBracket");
+
+module sideSupportRailBase(type) {
+
+  railLength = 100;
+  railBaseThickness = 2;
+  railBaseWidth = 18;
+  railSideThickness = 2;
+  railSideHeight = 12;
+  sideDy = -2;
+
+  frontMountPad = 10; // depends on y of box to be mounted TODO calculate this
+  sideMountPad = 10; // depends on x of box TODO calculate this
+  // distance between front and back main rail screw mounts
+  screwMountDist = 62; // TODO calculate this instead of hardcode
+  // vertical distance between local origin and main rail screw mount
+  screwMountGlobalDz = screwDiff / 2.0;
+
+
+  applyMainRailMounts()
+  sideSupportRailBaseHolder();
+
+  module sideSupportRailBaseHolder() {
+    if (type == "lBracket") {
+      sideSupportRailBaseLBracket();
+    } else {
+      error("Unsupported side support type");
+    }
+  }
+
+
+  module applyMainRailMounts() {
+
+    apply_p() {
+      translate(v=[0,frontMountPad,0])
+      union() {
+        dualMount();
+
+        translate(v=[0,screwMountDist,0])
+        dualMount();
+      }
+
+      children(0);
+    }
+  }
+
+  module dualMount() {
+
+    blockHeight = railSideHeight - sideDy;
+
+    difference() {
+      // mount block
+      translate(v = [-sideMountPad, 0, sideDy])
+      cube(size = [sideMountPad, 10, blockHeight+sideDy]);
+
+      // screw mount
+      translate(v=[-5,5,5]) // screwMountToGlobalZ
+      rotate(a=[90,0,0])
+      rotate(a=[0,90,0])
+      hexNutPocket_N(rackFrameScrewType, openSide=false);
+    }
+
+  }
+
+  module sideSupportRailBaseLBracket(backSupport=true, backThickness=3) {
+
+    translate(v=[0, 0, sideDy])
+    union() {
+      cube(size = [railBaseWidth, railLength, railBaseThickness]);
+      cube(size = [railSideThickness, railLength, railSideHeight]);
+
+      if (backSupport) {
+        translate(v=[0, railLength-backThickness, 0])
+        cube(size=[railBaseWidth, backThickness, railSideHeight]);
+      }
+    }
+  }
+
+  module sideSupportRailBaseDovetail() {}
+
+  module sideSupportRailBaseBoxed() {}
+
+}
+
+
+