If you need to align one shaft very precisely with another some distance away, this device can do so very well. It uses a small off-the-shelf, $20 laser from Amazon: http://amzn.to/1g4Jx9C And a regular CR2032 battery to power it: http://amzn.to/1UBTjO0 (disclosure: Amazon affiliate links) To assemble, bolt it onto your shaft. Use some scotch tape to tape the bare wire leads to the battery, and insert the battery in the slot from the top, followed by the laser. The hole is the exact size of the laser module, so it should fit in there very snugly, very securely, and very concentrically. The laser will be on permanently at this point, until the tape is removed. Rotate the shaft slowly and let the laser hit a wall or whatever far away, say 20' or so. The top of the authenticator is connected to the mounting plate by a thing neck which strikes a balance between rigidity and flexibility. Using the top four bolts, the laser can be angled very precisely on that neck with respect to the base-plate and shaft. As the shaft spins, the laser will trace a circular path when out of alignment with its shaft. Notice as it spins which side the laser runs out on and, on the four top bolts, loosen that bolt a bit and tighten the other side to flex the laser a bit in the other direction. Continue adjusting the 1/4" tension bolts in this fashion until it remains just a point as it is rotated. The joint on the bottom acts like a wobble plate, allowing the laser to be minutely adjusted to within millionths of an arc-second, depending on distance. The fact that the point of the laser is shining on something far away means that you can get it incredibly-well aligned to the shaft. With the laser now well-aligned to your shaft, you can align your shaft to the axis of rotation of a bearing system, or another shaft, with extreme precision, which will allow you to eliminate both vertical, horizontal, and angular misalignment. It uses 5/16" screws for the mount, and 1/4"-28 for the wobble-plate.