Extension spring systems should always be restrained by a safety cable that runs through the middle of the spring, tying off to a solid point at the rear and front of the horizontal door track. Extension springs represent a hazard to bystanders when a spring, pulley, or cable breaks under tension. Metal parts from extension spring systems can suddenly be launched.
(The Wahl correction factor accounts for additional stress in the material due to shear forces, although these forces do not contribute to the spring's torque. These shear forces become significant in designs using a low spring index, which is to say, a relatively thick wire for the coil diameter. The correction factor is applied to scale up the stress S to better predict the fatigue lifetime of the spring.)
The prior clamping of the set-screws tends to have pressed a dimple into the hollow shaft and to have distorted the shaft's roundness into an eccentric shape. While releasing the set-screws, I was careful to loosen them enough to let the cone swing around any such distortions. I was also careful to observe any binding of the old cones on the eccentricity or burring on the shaft. The fit of the cone on the shaft is supposed to be loose enough to avoid binding, but if it were to occur one would have to be careful not to assume the spring was unwound when in fact the cone was just stuck on the shaft. If I had a stuck cone that I could not unwind with a little extra force, then I would have called in a technician to deal with it. In the worst case, I suppose the spring must be deliberately broken with some hazard, thus releasing it for a forceful disassembly, and the shaft and some other parts replaced. But this is an unlikely situation and in this case was not necessary.
Here are the new replacement springs I ordered from a distributor, which I found using a Google search for "garage door supply" (search that phrase now). You certainly won't find these at Home Depot or Lowe's (although last I checked Lowe's does carry the less daunting extension spring replacements). I also have a list of some suppliers at the end of this page.
There’s another reason new doors are superior to old ones: energy efficiency. Keep in mind, garage doors are large, and when they open, they let a lot of outside air into your home. While you may have significant insulation separating your garage from the rest of your home, eventually that temperature differential will start to influence your energy bills.
Lift cable placement: On the standard residential door mechanism, the loops at the lower ends of the two lift cables loop over the two bottom roller shafts which project from the bottom bracket on the door. The upper cable ends fasten to the drums using one of the methods described above. The drums are positioned along the torsion shaft such that the inner edge of each drum is approximately over the edge of the door. The cable winds onto the drum from outside in, so at the top of travel the cable is winding onto the inner edge of the drum, vertical from the edge of the door where it is looped over the roller shaft. As the door is lowered, the cable winds out to the outer edge of the drum, and thus is a bit out from the vertical, but the cable still falls in the gap between the guide rails and door edge. My cables rub and slap on the rails a bit, but after 30 years and many 10,000s of cycles, they don't seem to have worn at all.
Those who benefit from this anti-competitive behavior have many excuses for it. They claim that the product is too dangerous and infrequently needed for the public to purchase directly. They say the job is hazardous and requires techniques and tools with which the amateur will rarely practice, which is true. They write me in anger saying I don't understand how expensive it is to put a truck on the road with a technician and parts and salary and benefits and insurance and advertising and every other common business expense. They say it will take the homeowner hours of effort to do this safely and correctly, while they can do it in a fraction of that time and at a price that isn't worth the effort to save. But should they set themselves up as the judge of what you can and cannot do? Of what is an economical use of your time? Imposing minimum order quantities or charging retail prices for small orders is legitimate; inquiring into the purchaser's background is not.
Fortunately, owners aren't bashful about weighing in on their garage door openers. Though some models get only a handful of reviews others receive hundreds of unique ratings on sites such as Amazon, Home Depot and Lowe's. If you are interested in a Craftsman garage door opener, Sears is the place to visit. While our research reveals that no garage door opener is perfect, several models jump to the fore as offering good performance and good value in the eyes of owners. These are the openers that we've named Best Reviewed for this edition of our report.
We believe we should treasure our natural resources, and our business practices reflect this ideal. All our service vehicles are flex-fuel efficient hybrids. When we have to throw away old parts, we recycle as many parts as possible. We clean up our trash after we complete a project. Our dispatch center is conscious about our carbon footprint and we use GPS technology and strategic planning to reduce our miles on the road.
In this article, we’ll tell you the difference between a safe door and one that’s unsafe. We’ll also give you the helpful tips you’re not likely to find in the manufacturer’s instructions to correctly, and safely, install a new door with a torsion spring and do-it-yourself tensioning. Installing a new, double garage door yourself will save you several hundred dollars and should take eight to 12 hours if you’re fairly handy. You can do most of the project yourself, but you should recruit help for removing the old door.
Insulation, which increases energy efficiency and can help to lower utility bills, is crucial when a garage door is attached to the home. In this case, doors with high R-values are preferred. This means it has insulation that can keep the heat in. The higher the R-value, the better insulated your garage will be against outside noise and cold and hot air.