So my eyesight is getting bad. Myopia, presbyobia, astigmatism, you name it, I got it. It's kinda embarassing when for the umpteenth time a colleague comes up to me and asks why my laptop screen resolution so low ah?
Anyway, its not the end of the world. Most people will get there someday, it's just that mine has accelerated I guess. Hopefully it's stabilizing and doesn't get any worse. I've got a wonderful optometrist, who works at this place called Igard. He's a professional, masters degree in optometry, visiting fellow at AH and some local polytechnic too, and it normally costs 35 bucks to see him, but they have a tie up with my workplace so its free consultation. Basically, he says there's nothing seriously wrong, and this happens to the best of us I guess, so I have reading glasses for the long hours of work, but regular glasses are fine for the most part except I got to make the font sizes a little bigger. OK, a lot bigger.
It's been a while since I've got the problem fixed so why only start blogging about it now? Well, there's a lot of other young people out there with a multitude of vision problems, especially since Singapore has the highest rate of prescription eyewear in the world (70% of all people). And I recently noticed other people of my age having problems reading. If you think u got problems with your eyesight, better go see a proper professional optometrist. Most of the quacks out there don't know nuts, and if you don't fix it fast with the proper eyewear, it'll only get worse!
And why do u need a professional? Well, I gotta tell u it took a considerable amount of effort for the guy to make sure I didnt have any other eye ailments such as glaucoma, macular degeneration, etc etc, and then a lot of effort using some laser and all that stuff to determine the right glasses alignment and all that to get it done right. Your typical quack who just uses the eyechart is gonna miss something I tell ya. Don't settle for anything less when it comes to your eyes! ;)
Tuesday, May 16, 2006
Sunday, May 14, 2006
skate bearings
The new skates have arrived! They really are a major improvement over the old ones. Itchy fingers me just removed an axle to take a look at the well lubed shiny ILQ-9 bearings, aren't they just a beauty?
It was then that I realised I don't know how much exactly to tighten it when I put it back! I searched online, and there are a couple of tips, but it hadn't occured to me that it was such a complex system. After all its just a screw onto an axle that holds the wheel bearings together...
One guy on an online forum says that it don't matter how much u tighten the axle, because its the bearing racers (the middle part of the bearing that sticks out) that gets squashed, and since its supposed to remain still anyway, why bother how much u tighten it? I totally agreeed with him at first. Then a pro replied saying that in order to have bearings not wear out excessively fast, it needs perfect alignment, and a thousandth of an inch out of alignment (or somewhere along that order of magnitude) could screw up the whole thing. Since most products aren't that precise, screwing the axle too tight would actually place your bearings out of alignment and they wont be able to adjust themselves when skating!
Ok, so you don't want to overtighten then. So be on the safe side and undertighten? That doesn't work out too. If you undertighten, the bearings spin around the racers, and the racers spin too, which causes a click click sound while skating and wears out the whole setup too! Argh!
So, to get it all right, you need perfect tightness, so that its barely tight enough and there's minimal spin of the racers when you spin the wheels freely, but no spin of the racers at all when the wheels spin while u skate. And how to achieve that? Well, tighten the wheel until it just barely doesnt move anymore when u try to twist it. Easier said than done though, especially when you are dealing with all these parts with low stiffness! For now, I just try to tighten it to the same amount of twist as the brand new axles that I haven't fiddled with yet. Will let u know what happens after the first wheel rotation.....
It was then that I realised I don't know how much exactly to tighten it when I put it back! I searched online, and there are a couple of tips, but it hadn't occured to me that it was such a complex system. After all its just a screw onto an axle that holds the wheel bearings together...
One guy on an online forum says that it don't matter how much u tighten the axle, because its the bearing racers (the middle part of the bearing that sticks out) that gets squashed, and since its supposed to remain still anyway, why bother how much u tighten it? I totally agreeed with him at first. Then a pro replied saying that in order to have bearings not wear out excessively fast, it needs perfect alignment, and a thousandth of an inch out of alignment (or somewhere along that order of magnitude) could screw up the whole thing. Since most products aren't that precise, screwing the axle too tight would actually place your bearings out of alignment and they wont be able to adjust themselves when skating!
Ok, so you don't want to overtighten then. So be on the safe side and undertighten? That doesn't work out too. If you undertighten, the bearings spin around the racers, and the racers spin too, which causes a click click sound while skating and wears out the whole setup too! Argh!
So, to get it all right, you need perfect tightness, so that its barely tight enough and there's minimal spin of the racers when you spin the wheels freely, but no spin of the racers at all when the wheels spin while u skate. And how to achieve that? Well, tighten the wheel until it just barely doesnt move anymore when u try to twist it. Easier said than done though, especially when you are dealing with all these parts with low stiffness! For now, I just try to tighten it to the same amount of twist as the brand new axles that I haven't fiddled with yet. Will let u know what happens after the first wheel rotation.....
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