An adaptation/improvement on http://www.thingiverse.com/thing:53301 for my K40 cheap Chinese laser. This one is modified: Like the other one, when you close the door, this lifts out of the way of the burning beam. Remember to hold it up if you're testing with the door open!The laser is a cheap 6mm pointer module (http://amzn.to/1hP4OoM), You can see how it's laid out in my machine (the big "target" has a ridge that indicates where the laser should be). There's a small pocket in the arm and the hinge to accept a ball-point pen sprint for a positive position when opened (you might need to file the arm/hinge just a bit so the action is smooth). There's also a 3mm hole for a setscrew if you nee to adjust the arm angle (since I made it for my machine, I don't ;) On my K40 unit, the L bend for the door this mounts to was not level/straight with the bed; a little finagling with a pair of vise-grips fixed that... No support is needed once you find which way to lay each piece -- the arm and the hinge both have flat sides, and my 3d printer didn't have a problem printing the post in the arm since it doesn't stick out very far. Remember to lift the arm out of the way if you're firing with the door open!