I obtained my parts, as described on this page, from American Garage Door Supply Inc. (http://www.americandoorsupply.com/) They may have raised their small-order prices or imposed a minimum order since I ordered from them in 2002 at the prices in my essay above. The Web site offers a free catalog by PDF download or mail. Springs in 2005 were priced at $2.25/lb.
You may enter your information on this website, visit an in store associate or call our garage door repair team at the number at the top of this page. Within 24 hours you will receive a call from a local service provider to discuss your requested service. Afterwards, you will schedule a date and time for the service provider to come to your property.
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.

(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.)
Unmatched or mismatched spring pair: You may find that you have a pair of springs that are different sizes. This mismatch may be a normal application, since the total torque on the torsion shaft is simply the sum of the torque contribution of each spring (indeed, very large doors can be lifted with 4 or more springs along the torsion shaft). The sum of the torque rates determine the lift; and dividing the torque among multiple springs does not change this. Some repair shops even apply mismatched pairs deliberately, since a few stock sizes of springs can be combined to fit a wider range of door weights than only matched pairs. For example, a technician may carry springs in increments of 20 lbs of lift, and when using pairs this allows a 20 lb increment in possible choices instead of 40 lb increments. Or, one spring from a pair may have broken and been replaced with a spring of equal torque rate but different size than the original.
Uncentered center bearing plate: The center bearing plate need not actually be in the center. It doesn't much matter where it is, since the purpose of the bracket is to anchor the spring ends. This anchoring must be secure, since all the torsion is held together at that point. On a stud-framed wall, this bracket may be placed over the stud closest to the center rather than exactly at the center of the door opening.
With over 300 independently moving parts, your garage door is a deceptively complex piece of equipment. To help prevent malfunctions and break-downs, it is a good idea to occasionally perform a garage door tune-up to keep all of these parts in good working order. A regular tune-up service by a Sears professional can prevent unexpected door problems and prolong the life of your existing equipment.

Garage Door Repair Company