You might be thinking: Aha! Why don't we lift the door, clamp it in place, and install the springs while they are thus safely unwound, rather than deal with all that accumulation of hazardous torque? The answer: At the top-of-travel, the unwound springs are not fully relaxed; they are still clamped to the torsion shaft with a significant stretch along the shaft axis, plus about a half-turn to keep the door snug at the top. This extra length amounts to the stacking of extra turns that accumulate from winding, also termed "spring growth" in the business. In my case this is about 7 turns of 0.2253 wire, or about 2 inches. Stretching the spring that much and clamping it with a half-turn or so of twist is not feasible.
Spring rate, torque, and lift: The spring rate K for these measurements is π*28.5*10^6 * (0.273)^4 / (32 * 140 * 1.72) = 64.5 IPPT. Applying 7.5 turns on this rate will yield a torque of 7.5 * 64.5 = 484 in-lb, which on the 4-inch drums (2-inch radius) yields a lift of (484 in*lbs)/(2 in) = 242 lbs. Again we find good agreement with the approximate door weight of 238 lbs.
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Spring stretch: When the door is at the top of travel, the spring(s) are hardly wound, but are stretched, so on a single-spring installation this stretch tends to pull the shaft towards the non-spring side. With two springs, the stretch tends to cancel out. This top-of-travel spring stretch, being about 7 or 8 turns of the wire, will thus amount to upwards of about 2 inches on a typical size spring of 0.253 wire. This spreads out to a gap of about 0.020" per coil on a typical 100-coil spring, so the stretch is not very visible.
The Heavy Duty Chain Extension Kit for 8 The Heavy Duty Chain Extension Kit for 8 ft. High Garage Doors is required for reliable everyday operation of Chamberlain heavy duty chain drive models in 8 ft. garage door applications. Featuring a quick-install extension rail and replacement chain the kit includes everything needed for quick and easy installation. Includes ... More + Product Details Close
As we’ve mentioned before, springs are installed within your garage lift mechanism in order to help lift the door. Because doors are so heavy, the lift motor would undergo far more significant wear and tear if it had to lift the full weight of the door every time you opened it. Furthermore, in order to ensure that you can open your door even if you lose power in your home, springs allow you to lift the door by hand when the motor is disengaged.
This work is risky, but the risk is comparable to doing your own car repairs, or climbing on the roof of your house to clean your gutters. These are dangerous things that many people can do safely, but that safety depends on intelligent understanding and application of proper techniques. Professional door repair technicians, who are fully knowledgable, skilled, and experienced, report that they nevertheless are injured from time to time, despite their best efforts. Coldly evaluate your abilities and motivations, to judge whether you can manage the risks of this work for the benefit of the money and time you might save.
Clopay® is proud to be the largest manufacturer of residential garage doors in North America and recognized as the leading brand among homeowners. For more than 50 years, we have helped homeowners reimagine their homes and create a personalized exterior that they can enjoy and take pride in for years to come. Clopay’s residential garage doors are designed and manufactured in the USA, starting at our headquarters in the heart of Ohio, and delivered to dealers via our 50 distribution centers throughout the US and Canada.
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.
When ordering springs, be aware that a number of different sizes of springs will make proper replacements, not just the specific size being replaced. The wire size, winding diameter, and length can be traded off to make springs of varied geometry but equivalent torque characteristics. This will also affect the expected lifetime (in cycles) for the spring(s). Since the critical specification for a replacement is the weight it is designed to bear, not the sizes per se, there are likely several stock sizes that replace a given old spring. The spring distributor's inventory may happen to offer only a different size with an equivalent weight-bearing specification. One has to judge whether to trust the advice of the seller in such situations. The seller should have the data to know what substitutions are proper.
By watching the chalk mark while winding, you can count the number of turns applied, and confirm the number later. My standard-size door (7 foot height) with 4-inch drums has a nominal wind of 7-1/4 or 7-1/2 turns, which leaves 1/4 or 1/2 turn at the top-of-travel to keep the lift cables under tension. After 7 turns on the first spring, I clamped down the set-screws, weighed the door again, and found a lift of about 100 pounds in reduced weight. As expected, this wasn't quite half of the full 238 pounds, nor would it leave any torsion at the top-of-travel, so I added an 8th turn. The door now weighed 122 pounds on one spring, which was ideal. After winding the other spring, the door lifted easily, with only a few pounds apparent weight. This confirmed that the spring choice was properly matched to the door design. I engaged the electric opener trolley, and adjusted the opener forces down to a safer level suitable for the new, improved balance. The door was now ready for return to service.
Resetting the drums, if needed: If the drums were incorrectly set in their old positions, one must reset both drums in new positions on the shaft. This is complicated by the presence of old dimples in the torsion shaft from previous setting(s), which must be avoided lest they improperly influence the new setting of the drums. To begin this process of resetting the drums, the door must first be lowered and resting level on the floor, the spring(s) must be in the unwound condition with their set-screws loosened, and the lift cables wrapped around the drums. If for some reason the door does not rest level on the floor, such as the floor being uneven, then insert temporary shims between the door bottom and the floor to bring the door up to level. Loosen the set-screws on the drums, and turn the torsion shaft to avoid the old dimples from the set-screws in the old drum position. Tighten the set-screw on the left drum (that is, on your left as you face the door from in the garage), creating a new dimple, and apply tension to its cable with the locking-pliers technique, enough tension to keep the cable taut but not enough to start to move the door up. Attach and wind the cable on the opposite (right) drum by hand until the cable is similarly taut, and set the screw, remembering that tightening the screw will tend to add a bit of extra tension to the cable. Both drums should now be fixed on the torsion shaft, with the cables about equally taut (listen to the sound when you pluck them like a guitar string) and the door still level on the ground. Setting the left drum first, and the right drum second, will allow you to take up any slack in the cable introduced by the left drum rotating slightly with respect to the torsion shaft as you tighten the set screws. This alignment and balance of the cables, drums, and door is critical to smooth operation and proper closing. If you have a single-spring assembly, the distance along the torsion tube from the spring cone to one drum is longer than to the other drum, which allows a bit more twist to one side than the other, and you may have to compensate with the setting of the drums.
The Chain Drive Rail Extension Kit for 10'-High The Chain Drive Rail Extension Kit for 10'-High Garage Doors is required for reliable everyday operation of Chamberlain chain drive models in 10-ft. garage door applications. Featuring a quick-install extension rail and replacement chain the kit includes everything needed for quick and easy installation. Includes one-year warranty rail extension replacement ... More + Product Details Close
Garage Door Installation – This includes the installation of a new garage door. Includes the door itself, the track, cables, springs, hinges, handles, locks and rollers. It is the complete service and installation of a new door. We inspect all the parts, make adjustments to fit your garage opening, and service all elements during the installation process. Plus, we check to ensure all parts are in proper working order after installed.