February 18, 2012 — 0038

Carburetor disassembly

Finally! A full can of carb cleaner, half a can of WD-40, four days of soaking, many hours of scrubbing and scraping, and a couple of damaged jets and stripped screws later, I have the carburetors disassembled and cleaned of all that sticky tar.

There are parts from all four carbs laid out there. The two missing bodies and float bowls, the “spares”, are still soaking; turns out that dry corrosion is much worse for moving parts than 30 years of semi-liquid gum and varnish. Corrosion eats right into the parts, chemically bonding them together and ruining surface finishes, but that black tar did a surprisingly good job of preserving whatever it was sitting on. Though a couple of minor pieces were damaged in removal or just plain fell apart from age, all told I have more than enough pieces to make two good-condition Keihin 722As and maybe a third.

Next step — reassembly! And maybe polishing the outsides if I can pick up some more polishing compound for the Dremel. I’ll probably end up painting those badly rusted top covers (far left) but the rest of it would look just fine as bare, clean aluminum, I think.

December 27, 2011 — 1412

Japanese waterstones

I got a Japanese waterstone for christmas. I’ve wanted for some time to learn how to sharpen an edge properly on a stone, rather than with one of those little sharpening jig things. There’s an old oilstone sitting in the basement somewhere but it always clogs extremely fast…from what I’ve heard, waterstones are generally faster and cleaner and fairly straightforward to use.

(Lee Valley)

I soaked the stone for half an hour to get it properly loaded, and watched a couple of videos online to get the idea of the proper technique. With time you apparently develop a sense for how the blade is sliding on the stone and the sounds it makes to know if you’re working it properly, but at this point I’m only really able to tell by feeling the edge and trying to guess whether it got sharper or duller. 😛

So I sharpened a whole bunch of knives, starting off with some of the cheap old ones sitting in my toolbox to get the idea. Getting the angle right is critical, of course, and the required pressure was more than I expected. I think I did a decent job: I turned a completely dull and rusted knife that I found on the road into something that’ll cut a tomato, got my pocketknife sharp enough to slice paper like an X-Acto blade at the tip, and honed a Japanese carpenter’s knife into an edge sharp enough to shave with. Seriously. It’s pretty clear from that how the different grinds and steels affect the sharpness of the blade — the Japanese knife has the shallowest grind and is made of very hard, very brittle high-carbon steel, while the Found Object knife has a pretty steep grind and the blade is flexible, so it’s probably mild steel or something equally cheap. Of course that does mean that the Japanese knife is fragile, while the Found Object stands up to much more abuse. Always a tradeoff.

My sister says I look like a sociopath sitting at the kitchen table slowly sharpening a pile of knives one by one. But any boy scout can tell you that a sharp blade is safer than a dull one…and besides, who doesn’t like having nice tools?

December 15, 2011 — 1612

Fixed the power drill

I got the aforementioned power drill with great bearings all cleaned up and working beautifully again! I decided to make a separate page about it, though, so you can find that over here. Suffice it to say this is one heck of a piece of machinery, and a design lesson to boot.

December 09, 2011 — 1637

This is a good bearing

I’m repairing a power drill (more on that later), and I found inside it a rather excellent ball bearing.



* Why is “ball bearing” a synonym for “steel ball”? A ball bearing is a bearing, i.e. a rotary fitting that supports a spinning shaft, that uses balls to reduce contact area. It isn’t a marble made of steel. I’m guilty of calling the balls “ball bearings”, but the more I think about it the more I wonder why we needed a more obscure and less accurate metonym for “steel ball”.