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.

You can reschedule or cancel your service at any time. To reschedule, simply go to Your Orders, find your service order and click on the ‘Contact Provider’ button on Your Orders page. To cancel, click on the 'Cancel Order' button on Your Orders page. Payment goes to the pro from your secure Amazon account. Because you aren't charged until the actual work is completed, cancelling a job doesn't require a refund.
As noted above, set-screw clamping may have distorted the cross-section of the shaft and made it difficult to slide off all the hardware. With the shaft on the floor, it may be possible to restore enough roundness to proceed, using compensating clamping force to the distorted area via a machinist's vise, an arbor press, a hydraulic shop press, etc., on the shaft body. Burrs and other slight distortions on the shaft can be filed off with a hand file or touched with an abrasive wheel on an angle grinder. At some point, the condition of the shaft may just be degraded enough that it ought to be replaced.
Speed of a falling door:: Physics tells us that the transit time of a free-falling body is sqrt(2x/g), where x is the length of the fall and g is the acceleration due to gravity (32.2 ft/sec^2). If this typical 150 lb door were to fall an equivalent of 3.75 feet, this falling time would be sqrt(2*3.75/32.2) = 0.48 seconds (480 milliseconds). The terminal velocity is gt, or 0.48 seconds * 32.2 ft/sec^2 = 15.5 ft/sec = 10.6 mph.
While many sites may encourage you to save on garage door replacement costs by installing the door yourself, this is severely discouraged due to safety concerns and the installation techniques and tools required to properly and efficiently replace a garage door. When installing a new garage door, the range of prices also includes the labor performed by the professional garage door technician. These costs can include:
Ryan came to my rescue within 6 hrs of my call. He was professional, knowledgeable, friendly, and very thorough. He got my door up and running after figuring out what 3 others could not! Don’t try and go the cheapest route like I did because you’ll end up wasting time and money. Hire the pros like Ryan FIRST! If I ever need someone in the future, I’ll be calling them first thing! HIGHLY RECOMMENDread more
The door and tracks at this stage of the repair are in a minimum-energy condition. This is a good opportunity to work on any hinges, bearings, rollers, cables, or tracks that need tightening, repair, lubrication, or replacement. Again, these parts should be available from the spring source, and should be ordered based on a pre-inspection. Home-improvement stores carry some of these parts, but the type and quality may not be the best.
Measurements: With the door in the down position, I measure a wire size of 0.273 inches, outside diameter of 2.0 inches, and overall length of 41.5 inches. Relaxing the spring shortens the length by about 7.5 coils of wire, so to estimate the relaxed length, we deduct the wire diamter of 0.273 inches times 7.5 from the 41.5 inch wound length, yielding an estimated relaxed length of 39.5 inches. The mean coil diameter is 2.0 - 0.273, or 1.73 inches. Perhaps this was actually a 40-inch-long spring with a 1.5 ID, 1.75 mean diameter, and 2.0 OD, but let's continue on calculating with the actually observed sizes. The number of coils in the relaxed spring is the relaxed length of 39.5 inches divided by the wire size of 0.273 inches, or about 145 coils. Deducting about 5 dead coils at the ends yields 140 active coils.

Absolute Overhead Door recently launched a blog that can be found here so that readers would be able to see the benefits of a garage and what they should do in the event their newly driving teenage drove into the garage door. The blog offers many tips for “fix at home” solutions as well as giving examples of situations when calling us for a service call is the best decision. In our blog, we give professional and honest recommendations for the most reader and budget friendly options for families looking for advice that doesnt cost a fortune and an obligation to purchase a new garage door from a salesman afterwards! Check it out! We hope you enjoy it.
Looking for a distinctive overhead door? At PK Garage Door, we have the one to fit your specific needs. In the garage door industry for over 30 years, we know all their ins and outs. What sets us apart from our competition? Our personalized customer service! For us, every customer is unique, just like their needs. Because we work exclusively with top quality products, we carry Garaga as our garage door line. 

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Ryan came to my rescue within 6 hrs of my call. He was professional, knowledgeable, friendly, and very thorough. He got my door up and running after figuring out what 3 others could not! Don’t try and go the cheapest route like I did because you’ll end up wasting time and money. Hire the pros like Ryan FIRST! If I ever need someone in the future, I’ll be calling them first thing! HIGHLY RECOMMENDread more
Cycle lifetime unchanged by diameter-versus-length tradeoffs: Since the material stress (and thus cycle lifetime) for equal torques varies only with d, and not D or N, trading coil diameter (D) for spring length (N) in this fashion has no effect on cycle lifetime. Long and skinny, versus shorter and fatter, they'll wear the same if they have the same wire size and diameter-length product. The game of life is all about wire size when it comes to springs (see below).
Looking to repair your garage door opener? Common problems could range from issues with the remote or wall switch that control the garage door opener to more serious issues like a grinding noise coming from the opener itself. If you need help with repairing your garage opener, schedule a repair appointment today! We repair all major brands and have same-day availability in most markets, so we can get your garage door opener repaired and running smoothly.

Dodging a falling door:: Reversing this equation gives us x=gt^2/2 as the fallen distance x for a given time t. How much time would you have to dodge a falling door if the spring were to suddenly break at the top of travel? Let us assume you are 5.5 feet tall, so the door will hit your head after falling 2 feet from its 7.5 foot fully-raised height. This 2-foot fall takes sqrt(2*2/32.2) = 0.35 seconds (350 milliseconds). The quickest human response time is about 200 milliseconds, so even if you are alert to the hazard, this leaves you only about 150 milliseconds to accelerate and move your noggin out of the way. If you are an Olympic gold medalist in the 100 meter dash, you can accelerate (horizontally) about 10 feet/second^2, and your 150 milliseconds of wide-eyed panic will move you all of 10*0.15^2/2 = 0.11 foot = 1.35 inch.
Squealing, screeching, or grinding noises from your garage door are usually indicative of a lack of lubricant or an accumulation of dirt or debris in the tracks. When removing debris, do not use harsh chemicals to clean the tracks. Once the track is clean, coat it with lubricant designed especially for garage doors, if possible. If you do not have access to this special type of lubricant, you can use WD-40 on the tracks and hardware.
You might genuinely need some extra parts when you thought you simply needed a broken spring replaced, and a good serviceman will perform a simple inspection to identify such parts. Nor is it unreasonable for a business to charge separately for a service call versus repair work actually performed. But the best protection for you as a buyer, being somewhat at the mercy of whomever you decide to bring on site, is to understand what is being done, and ask intelligently for a clear explanation or demonstration of why extra parts are required.

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