Wednesday, July 08, 2015

I Fix Something Without Breaking Anything For Once

After a week's aggravation doing battle with the Bloody Long Island Railroad it was time to get the rubbery mud out of the pool1.

The new plan called for all that stuff to come out and be replaced by something else, the exact nature of the something to be decided after I had had a good look at the landscaping cloth to see what was what. I'd soon have this pesky pool problem under complete control. Friday was July 3rd, a holiday2 and since I was on forced downtime I set aside that day for rubbery mud removal operations. I sent the Stevieling, ordered by Mrs Stevie to remain in-theater and to help, to get the shovel out of the garage and she returned complaining that the door was stuck again.

For some reason, the Stevieling has an unerring knack of getting the cables of our beaten-up garage door to jump off their pulleys by just looking at them, though I should mention that the right hand side cable was not functioning properly owing to some loose strands getting jammed in the spring pulley works some years ago. The cable needed replacing yonks ago, but I couldn't get the U-shackle that secures it to the frame off and at that time was uninspired on how to cut the cable - a number of attempts having come to naught due to lack of space for hacksawing etc. - so I was putting it off. The door had gradually become harder to open as the cable deteriorated3 but my natural laziness and other problems forced the issue from my mind.

I heaved a sigh4 and climbed back out of the pool to see what was going on this time.

What was going on was that the right-side cable had frayed to the point it would not feed through the static pulley so the right hand spring was unavailable for door-counterweighting duty. It was also now made of so few actual strands that the lethality had swung up to Castle Bravo levels, and the proximity of the Stevieling triggered some sort of hitherto latent parenting hormone which sharpened my perception and brought that aspect into strong relief, clearing the buffers of all other concerns and excuses. Action Was Called For™.

For those not familiar with the standard garage up and over roller door, the way it all works is that the door is segmented rather like a roller-top desk lid is. At the very bottom of the door, on either side, there are buttons like those used on guitars to mount a strap. In this case they are used to mount the loop end of a steel hawser about an eighth of an inch thick made of braided steel wire.

The door has little wheels that run in curved tracks on either side to guide the door up and overhead as it is raised. To assist in lifting the door two steel cables, one either side of the door, run up alongside the frame the track is mounted to, over pulleys mounted to the frame and then horizontally alongside the track to pulleys mounted on the end of two-foot long springs. Each spring is tied to the end of the track with a length of threaded rod in order to present the illusion that one can adjust the tension thereby.

Having passed through the pulley attached to the top the spring, each hawser runs back down its own length to the top of the frame where it is attached by feeding it through a small hole carefully positioned out of any possible sight-line and back once again down its own length for a short while, where it is secured using U-shackles to bind the end to the return length of cable.

So, to sum up, each cable runs vertically from the bottom of the door, around a pulley and then horizontally for about ten feet, around another pulley attached to a spring and back towards the door frame, through a little hole and is strapped to itself to stop the spring pulling it out of the hole and towards the back of the garage at great speed. Got that?

When it is working properly the door is pulled down, stretching the springs half the distance the door has to move5. When opening the door the springs offer a counterweight-like assistance, negating part of the door weight.

Modern garage doors are made of lightweight materials and offer no real problem if the springs are not adjusted properly or if one of the two block-and-tackle arrangements fails in some way to help lift (though they still get stuck if the problem occurs when the door is open and the wires fall off the pulleys).

The door of the mighty Steviegarage is made of sterner (and much heavier) stuff, being of sheet steel construction. Indeed, I believe the individual hinged panels once did duty as blast doors on a battleship, so sturdy are they. I was once almost killed one summer when the lift mechanism failed because I raised the door too high causing both cables to come off their respective buttons, and the door dropped sans springs, cables etc to crash mere millimeters from my anxiously wiggling toes, showering my unprotected shins and thighs with pulverized concrete shrapnel from the force of the impact.

It was what my father calls "a bloody job" jacking the door open so I could fix it too. Since that refreshing event I always prop a two-by-three in the right-hand track so that in the event the anti-handyman demons strike the door's lowest guide wheel will be arrested before things get interesting.

Now I had been putting off fixing that cable for months. I'd tried to undo the damned thing at the end of last September when it first started to fray in earnest, but the U-shackle securing it to the frame would not come loose. Now I could see the cable was demanding attention. I briefly considered simply clipping off the loose strands, then realized I was looking at a death trap and heaved another sigh. I didn't want this damned thing guillotining the Stevieling the same way it had tried to do me. She doesn't have the life experience to know when to deploy a Two-by-Three of Safety. Also, I saw I had a replacement cable hanging on the garage wall ready to be installed, so I levered the door wide open and propped it with my trusty two-by-three.

I grabbed my socket set, my Dremel tool and a set of snap-on cutting wheels and set to work. First job was to cut the old cable away. Using Mr Dremel and a cutting wheel and operating mostly by The Force in the absence of an available point-of-view to the work area I cut the cable where it doubled back from the frame to the U-shackle.

The cable cutting went surprisingly quickly, though the spray of sparks produced made the Stevieling think I was about to burn the house down and I was obliged to demonstrate that there was little heat in the sparks to calm her. This I did by taking a piece of the cable and cutting it such that the stream of sparks was directed against my T-shirt.

"See?" I said. "No danger at all."

"Then why is your shirt smoldering?" she asked.

"Global warming" I answered. "It's a little understood scourge but we must be ever-vigilant for its symptoms. Well done. Now hand daddy that bottle of water would you sweetheart?"

The cable remained stubbornly attached to the door frame even though I had cut the bit just frameward of the shackle. This was because the cable had been bent in a U-shape since Brontosaurs6 walked the Earth and was less bendy than the new one I had slowly unwinding and tangling around my feet on the garage floor. No problem. I simply reached up and located the thing by feel (no sight-line, remember) and gave it a series of carefully considered and scientifically proper mighty twisty pulls to reintroduce the cable to the idea of flexibility all the time making appropriate manly whimpering noises to encourage it. I kept my face close to the safety of the steel door, using it as a shield should the spring decide to get in on the fun and give the cable some help.

Which is, of course, exactly what happened.

The cable suddenly ripped out from between my fingers and went screaming back toward the garage's rear wall, taking time from its busy schedule to catch me a glancing blow on the right wrist as it did so7. Naturally, since the Stevieling was nearby, I eschewed my usual store of class three Words of Power set by for such occasions and contented myself with some manly howls of pain and thirty seconds or so bent double, jumping up and down while clutching the bleeding wrist and begging for death's sweet embrace. Then I went and put a Band Aid on the wound and got back to work.

Once I had the old cable unhooked from the door I could remove the fittings so I could begin what might be a fruitless search for an open hardware store with the right bits in stock. I cut the loop end off the cable and the U-shackle from the rest of the cable and cleaned up the ends with Mr Dremel so I wouldn't poke holes in the car or me. I set the Stevieling to guarding the contents of the garage (chiefly Troll, The Snowblower of Supreme Spiffiness, the lawnmower and the genny) and dashed to Arse Hardware to buy two new U-shackles and the soft lead thingy needed to form the loop at one end.

All of which went without a hitch even though this was the day set aside to observe the July 4th holiday (which fell on a Saturday this year) and which I expected might make for me running hither and yon in the fabulous Steviemobile in a vain attempt to find a hardware store that was open. Returning home I took the figure-of-eight shaped lead thingy, fed the cable through one hole and back through the other to form a loop (using the original cut-off loop as a guide) and using a combination of mighty blows with Finesse8 and mighty Words of Power I crushed the fitting so that the loop was firmly secured. I grasped the finished job in my hand so I could make a close examination of the work.

Important tip: When hammering ductile metal aggressively heat is generated, often in disconcertingly large amounts that stay around in the workpiece for a bit.

After that it was a relatively easy task to hook up the new cable and run it through the various pulleys etc. and anchor it to itself with the new U-shackles, especially easy when I realized that if the door were retracted all the way to the end of the track I could actually see where I was working. This required some inventive work with levers and blocks but no limbs were lost so it is hardly worth going into in depth. I soon had the cable secured with lots to spare should it need slackening.

The first test involved me standing inside the garage while the Stevieling closed the door but not far enough for the latch to engage. I observed everything working smoothly as I attempted to keep all the newly adjusted parts in view in case they made a bid for freedom. Even with Troll and the lawnmower removed there isn't much room for evasive maneuvers in there owing to the large amounts of crap stacked everywhere, so a keen eye was essential lest it be gouged out by a high-speed ballistic U-shackle or a pulley making a run for the border, but it all looked good.

The second test involved opening the door, which was so easy compared to the titanic effort it had required for the last few months9 that the Stevieling ended up throwing it back against the stops. This was a tense moment because the loop end hasn't had time to become teardrop-shaped from time under tension, and can escape the button on the door if the cable slackens, which then means the door is not properly counterbalanced and will come crashing down in a re-enactment of Murphy and The Bricks10, so we made a note to tell everyone not to do that any more.

The third test was to close the door fully and check it would stay closed and not inch open, which is what happened the last time I adjusted the other side cable to tension it a few months ago.

It all went very well so I used Mr Dremel to cut off the excess cable, we repacked the garage with the crap we'd removed so I could work and decamped for showers and lunch.
Nothing got done on the pool.

  1. According to the increasingly strident Mrs Stevie
  2. Something to do with a celebration of a treacherous mutiny by a bunch of colonial ingrates not recognizing the inherent benefits of benevolent British rule
  3. Engendering a potentially lethal situation, but I'm getting ahead of the story
  4. Pulling several muscles as I did so
  5. High school physics. Set up is like a block and tackle with a rope hanging from an eyebolt passing down and through a pulley in a block with a hook and back up to a ceiling-mounted pulley, thence to the floor. You reel in twice as much rope to lift twice as much weight through a given distance. Velocity ratio is 2:1 - the door travels twice as far as the spring stretches
  6. We are allowed to have them again it turns out
  7. Energy stored in spring was released. Spring retracted distance A. Thanks to velocity ratio (2:1) end of hawser moved distance 2A in the same time frame. Moving a given distance in half the time means that whatever it is is going twice as fast. The spring collapsed very quickly indeed so the hawser sped past at "better not get in the way" speed, shedding Cherenkov radiation as it went by my nose
  8. My claw-hammer
  9. Seriously. It required both hands and a powerlifter stance to get the thing open
  10. Also depicted in the second Babe movie in the incident at the well

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