Loosening or tightening the set-screws is the moment of most risk, since the end-wrench is a potential missile if you slip, and your hand is close to the cone. When the wrench is removed and only the rods are in place, it would seem that the worst that could happen is that the rod is flung out and the captive spring and cone rattle around, assuming you are keeping yourself clear of the rod's radial disk of rotation, and not leaning on the rod such as to fall into the apparatus were the rod to slip out of your grasp. The torsion shaft design has the virtue of capturing the mass of the spring and cones reliably on the shaft, preventing these parts from launching themselves as projectiles, even in an accident.
Another moment of truth arrives as the winding-up of the springs begins. (I am just posing here with the camera held out in my left hand. Except for lifting the door onto the scale, this was a one-man job, including the photography.) The position of the bars in this photo was necessary to take the photo, and does not show a correct winding technique, You should not have to swing the bar up as high over the top as shown. The lower bar during winding should swing from pointing down to pointing a little past horizontal. Then you hold that bar horizontal while socketing the other bar pointing down, apply force to that (now) lower bar, then remove the (now) upper bar, wind one-quarter turn, and repeat.
Most importantly, you will be greeted by friendly staff and associates that will help you select the right garage door for your home. We welcome the opportunity to supply, install, and/or repair your garage door as well as answer any door questions you may have. When you choose us, you will quickly discover why thousands of Riverbend area customers from house to house and generation to generation have chosen Dan's Garage Door Service as their “DOOR KEEPER” for over 40 years.
Garage door manufacturers typically produce garage doors fitted with torsion springs that provide a minimum of 10,000 to 15,000 cycles and are guaranteed for three to seven years. One cycle is a single opening and closing sequence. Most manufacturers offer a 30,000 cycle spring. However, it is important to remember that if the weight of the garage door is increased by adding glass, additional insulation, or even several coats of paint, the life of the torsion spring may be greatly reduced. Additionally, springs at highly humid environments, such as coastal regions tend to have a significantly shorter cycle life, due to the corrosive cracking.