Tuesday, December 10, 2013
Microsoft has updated its OneNote apps on Android and iOS to provide a more consistant look on all t
Huh...not like a love story at all. It sounded a lot better in the original write-up. Whatever. Anyway, after sadly turning in my keys at the end of the semester, I thought I'd never play with volatile laser beams again...at least until next year. BUT! My school has a Design, Build, Fly (DBF) team - although we always managed to catastrophically crash just before the competition...go figure - and a team member wants to get an early jump on manufacturing procedures in an attempt to revitalize the project. So whaddaya know, I'm now the go-to guy for lasers. Booya.
So it's time for a new saga! For years we've had these old central air supply and return vents in our hallway and garage. They're old-fashioned, impossible to clean, and bent up from years of hallway soccer and such games with four kids in the family. In short, they're ugly now, and too old to find a direct replacement. Custom or even stock metal covers are pricey...and mostly hideous. So what is the solution? Drab to fab and all that jazz - laser cut a new one out of wood!
The leading image is the final product for our garage vent cover. The second image shows a before-and-after for the hallway vent. Still a bit of work to do on that one - cleaning up the wall around the edges and such - but not too shabby overall. All of this work was done at the cost of materials and a bit of time on a CAD system, totaling perhaps $20 - because my usual wood shop was out of the size stock I needed, so I had to go to an art supply store, where they charge double. Figures.Well, turns out I'm not revolutionary in this respect. There are a handful of vent cover companies that will custom laser cut your design (or CNC mill metal or plastic), but still, they're expensive. I could ship a design to Ponoko or the like, but I'd pay at minimum $30 between cutting and shipping, even with their cheapest materials. So, once again, having a free laser and living near a handful of hobby shops pays off! I can CAD my own design and cut at material cost - for something like this I can use a cheap 3/16" plywood at $3 to $4 bucks a sheet and easily make new covers for my hallway and garage vents. Yay!
And then came the first roadblock. There are thousands of really nice vent cover designs - run a quick Google search for "fancy vent cover" and see what I mean. Granted, there are thousands of hideous ones, too, but while we want something modern-ish and interesting, we don't want a busy design. After all, it's a 15.25" x 7.25" (9.25") cover on a wall at shin level that will blend into the wall. This ain't the Ritz.
And then we found our second roadblock...coincidentally right next to the first. Our garage vent (seen in Step 1) has vertical bars. It hides the largest duct hot-air delivery duct in our house - a whopping 6 inch hole in a sheet metal box. Beautiful, eh? But the vertical lines in the old vent fail to disguise this...and most of the designs in Google searches have large amounts of blank space between straight lines or curvy designs. Not good. Too much blank space in the vent will leave an eyesore very visible - even at shin level - and too little will block our airflow (we use what once was a garage as a den, sort of). Straight lines won't work, and we don't want a Fleur-de-Lis-type pattern that matches nothing in our house. What to do?
Optical illusion! In a random search, a new type of design appeared - one made of broken, overlapping, and intersecting circles. I was immediately reminded of the lovely ripple clock by fungus amungus - the overlapping rings broke up the circular edge until closer look, so this seemed like the way to go. Better yet, it's a simple, geometrical design, so it will be quick to cut and easy to CAD. Long search over! Hurrah!
The brake system has a ratcheting action. Every time you apply the brakes, the pistons press the brake pad against the rotor creating friction which slows the bike down and also results in loss of material on the brake pad itself. This wearing process occurs slowly or else we would be changing pads daily instead of after thousands of miles. When the lever is released, the pressure is released and a set of springs and a little bit of vibration and bumping from the rotor cause the brake pads to push the pistons backward slightly to remove the friction from the rotor. As the pads get thinner from repeated brake application, the pistons slowly move out of the caliper over time so that the brake lever engages more or less at the same distance from the hand grip. This is the so-called ratcheting action of the hydraulic brake system. As this occurs, the level of hydraulic fluid in the brake reservoir will be dropping so maintenance top-ups are required.
Over time, dirt and brake dust coat the pistons in the brake caliper. Some of this dirt may work itself into the piston seal when the pistons retract a bit after brake application. Sometimes, instead of the piston sliding forward through the seal when the brakes are applied, the piston gets stuck to the seal and rolls the seal forward when the brake lever is pulled. When the brake lever is released, the seal restores its normal shape causing the piston to be pulled backward. The ratcheting action is lost. As the brakes wear, the piston gets further and further from the friction point. The result is that the brake lever activation point moves closer and closer to the handgrip.
The speed at which the piston retracts back into the caliper due to elastic action of the seal is quite slow so 2 quick pumps on the brake lever generally result in the pistons making contact with the pads, and the lever works at the correct distance from the handgrip. The reason pumping works is because the first pump moves the piston outward as much as the hydraulic fluid pushed into the system from the hand lever allows, and the second pump forces additional hydraulic fluid in behind the piston which moves it out to the pad and generates enough friction to stop the motorcycle.
Crikey, a lot of words to describe this problem. So on with the fix.
Pesto sauces do not have to be made solely from basil. You can use almost any herb to make pesto. Pesto comes from the Genoese word pesta, which means to pound or crush.
I recently went on an adventure around my college campus and discovered a whole bunch of herbs that I used to make a pesto.
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