Mechanical Failures

Sump Pumps

We have two sump pumps in the crawl space under our basement floor. One was put in shortly after we built the house. The other was put in when we finished the basement. They both sit in perforated five gallon buckets that have been sunk into gravel lined holes about two feet deep and two feet in diameter. When we finished the basement, a perforated drain pipe was installed across the uphill side of the basement. It drains into the newer sump. Both pumps are controlled by float activated switches. When the water reaches a certain depth, the pump turns on and runs until the sump is empty, or nearly so. The switch on the first pump is inside a float that is attached to the pump by a power cord. It is free to flop around. The newer pump has a float that runs up and down a guide attached to the side of the pump. The five gallon bucket it sits in is just barely big enough to contain it, and sometimes the float would become stuck. When this happens the pump runs continuously, it never shuts off. I would periodically go down and check it, but it wasn't enough. After a couple of years of this abuse, it finally failed. I think it cooked itself. I pulled it out thinking I might be able to fix it. However when I took the top off the motor, I discovered that the motor housing was full of oil. Even if I could have fixed it, I wasn't prepared to deal with oil. So I put the lid back, set it in the garage, and went to home depot and bought a smaller pump with a floppy type of float switch. So far it seems to be working okay. And what I am going to do with old pump? It will probably sit in the garage till I retire, and then I'll throw it out. I called a couple of dealers about getting it fixed, but no one was interested. All they wanted to do was sell me a new one.

Radio Buttons

Saturday Ross and I fixed the radio in Mom's (Anne's) van. The volume on this radio is controlled by push buttons. One button increases the volume, another button turns it down. Every so often the down button gets stuck, and you can't turn down the volume anymore. You can still turn it up, but you can't turn it down. As this is the third or forth time this has happened, I have the repair procedure down to a science. Basically it involves removing the radio from the dash, taking the faceplate off and take it apart. The push button action is implemented with a flexible rubber sheet with bumps in it for each button. The problem is the bump for the down volume control gets stuck. Taking the faceplate apart allows it to pop back up. So now it's fixed, and it's just a matter of reassembling the faceplate and reinstalling the radio.

Taking the radio out is normally a onerous chore. On the Ford it is relatively easy, however, you do need a special tool. The special tool is a couple of pieces of wire, about the thickness of old wire coat hangers, bent in the shape of a "U", about three inches tall and an inch or two across. The ends of the "U" are something in the shape of crochet hooks. The ends of the U's go through holes in the front of the radio and disengage latches that hold it place. Theoretically speaking, you simple slide the special tools into the holes until the latches disengage and then pull to remove the radio. In practice, there is a good deal of pushing, pulling, yanking and muttering, but it eventually works, and it is much easier than having to take it out from underneath and behind, which used to be standard practice.

Tiny Screws

Sunday Ross and went shooting with a friend of mine in the Coast Range, about thirty miles west of our house. We found a gravel pit to shoot in, actually a hillside. A few years ago I bought a high-powered rifle with a scope in the expectation of going deer hunting. This is first year I have even shot it. It is very loud. It is at least twice as powerful as any of my other weapons. When I shoot it, I can fell the shock wave it produces in my entire body. Anyway, before you attempt to use a weapon like this, it is a good idea to "sight it in", i.e. to verify that the sights correspond with the trajectory of the bullet. So my friend and I tried a couple of shots each (Ross didn't want to have anything to do with it. The 22 caliber rifle is more to his liking) at some targets set up about 75 yards away, with inconclusive results. So we set up a larger, closer target, a sheet of particle board about four feet square about 25 yards away. We marked a spot
on the board and I fired about four shots at it. When we went to look at the board, it was apparently unmarked! But then we looked at the back side of board, and it was obvious that the board had been hit. There were large, ragged bunches of splinters sticking out. But even when we knew where the bullets hit, it was difficult to see where they had struck on the front side. And these were relatively large bullets, 30 caliber, almost 5/16" in diameter.

Anyway the four hits on the board were in a nearly vertical line, but they were spread out vertically over nearly two feet! What could cause this horrible inaccuracy? And then we look at the gun and notice that one of the scope mounts had come detached. The scope mount had been secured to the barrel of the gun with tiny flat head, Allen screws. Allen screws have a hex shaped recess to accommodate the driver. The cone shape of the screw head combined with the hex shaped recess combined to reduce the attachment point of the head to screw body to almost nothing, which made the screw very weak, and given the smallest task, it failed.

Ovenized Oscillators

At work I am working on a new radio transmitter. This radio uses a 10 MHz (ten megahertz, or ten million cycles per second) crystal controlled oscillator. Crystals are used in oscillators because they are very stable. If a crystal is generating a 10 MHz signal today, then it will be generating a 10 MHz signal ten years from now. However, the frequency generated is temperature dependent. If the temperature goes up, the frequency goes up. Not much, but for our purposes even the smallest deviation is unacceptable. So we use ovenized crystals. This means these oscillators contain a heating element that raises the temperature to the highest temperature that the crystal is expected to operate at, in this case about 140 degrees Fahrenheit (most Microsoft fonts don't have a degree symbol). I am working with on old prototype board and the crystal was attached to the board with double sided mounting tape (the kind used for hanging pictures on walls). This tape is made of foam to accommodate surface imperfections. This board had been used so much that the heated crystal had cooked the tape, which caused it to fail, which left the crystal dangling by its' wires, one of which broke. No big deal, we glued it back down using super glue and soldered new wires on.

Super Glue

A few weeks ago I tried to repair a die cast model tractor using super glue. It didn't stick the first time, so I filed the mating surfaces flat and tried again. Still no luck. Ended up using epoxy. Now the part I glued on has itself come apart, so I need more epoxy. Super glue is funny stuff. It will definitely stick to skin and to most other surfaces, but occasionally I will come across something that it won't stick to. Die cast metal for instance. A friend of mine speculated that it was because the metal is porous.

Camp Power

Once upon a time I read about a magnetohydrodynamic (MHD) generating plant that was built in the Soviet Union.

A MHD generator generates electricity directly from a flame. No engine, no boiler, no intermediate steps at all. Basically you have a couple of wire mesh grids in the path of a flame and you connect wires to these grids and you get electricity. Of course the grids are probably made of platinum or some other exotic substance, and the efficiency is not all that great, but you can't make a simpler machine.

I think a small generator like this would be a great power source for all sorts of remote locations, like our monitoring sites. It would also be great for campers and explorers, anyone who wants electricity where there isn't any other supply. Batteries, as demonstrated by our rooftop station this weekend, go bad.

I was thinking that one should be able to build a miniature MHD generator that would run on propane. Use it to generate electricity in remote locations to run radios. No batteries needed. As long as you have fuel, you have juice. Sell it to backpackers. Use it anyplace where you need a small amount of power, and you don't have, or don't want wires, and you don't want a big noisy generator set. I'm sure there would be a market for it if it could be built.

Neutron Propulsion

My big idea this morning is to use radioactive materials for propulsion for interstellar probes. (some?) Radioactive materials produce high velocity neutrons. Put your radioactive material in a heavy pot. Point the opening in the pot opposite the way you want to go. Thrust would be very low, but very long lasting. Don't need to worry about radiation, space is full of it. Just need heavy shielding in the pot to protect the rest of the spacecraft.

Details

Smoke Detectors

I have three smoke detectors in my house, all wired together, and all supplied with house current. The battery in the unit in the upstairs hall just failed for the second time. Neither of the other two units have ever complained. Why is that?

Optical Mouse

I got a Microsoft optical mouse a while back and took an immediate dislike to it. Everyone else in the family thinks it's just fine. But I use it play minesweeper and it was much more difficult to control than my conventional mouse. But then I sat down to play the other day and the mouse was working fine. It seemed to glide much easier. I think someone must have applied some furniture polish or something to the desk, because the mouse slide very smoothly. The problem was that the mouse was sticking to the desk just a little bit, so little that I didn't even notice it, but it resulted in jerky motion, which made it hard to control. For big motions it was never a problem, but for small motions, it was impossible.

Hard Boiled Eggs

I was peeling a hard boiled egg last night and it was being a real pain. You know how sometimes when you peel an egg the shell slides right off, but other times it sticks to the egg, and you have to pick each bit of shell off, and often it takes a bit of egg with it so you end up with an egg that looks like it's been through the war? What causes this? Why is it some eggs stick to the shell, and some don't?

Egg Replies:

I can share some egg knowledge. I heard that older, less fresh eggs peel easier than fresh eggs. Don't know if that's true or why it would be.

To hard-boil eggs, put them in a pan of cold water, heat to just boiling, turn off the heat, cover and let sit for 10 minutes, then plunge the eggs in cold water. I have pretty good luck with this method producing easy-to-peel eggs.

Some people like to pierce a hole in the fat end of the shell (just the shell) to allow the cooking egg to expand and shove the air out of the little pocket in the fat end of the egg. I don't know if this is worthwhile or not.

Now you have something to do this weekend. Good luck on your egg adventures.

-Dan




Note on egg piercing: Not worthwhile if you're hungry and have shaky hands.
Trust me.
Thank you.

Malia




Okay.....I have absolutely no knowledge of any scientific evidence that this is actually true...but I have found that if the hard-boiled egg is still hot/warm when you peel it, it tends to peel off easier. Could totally be a misconception on my part...or a just plain crazy notion...but it's the "rule of thumb" for this housewife!

Di

Lawsuits

Problem with this kind of stuff is that it makes great newspaper headlines, but how much of it really comes to pass? You hear all kinds of stories about lawsuits being filed, but you seldom, if ever, hear about anyone actually getting paid.

Just for grins, here is one anecdote that puts a slightly different spin on the situation.

Lawyer I know takes a minor automobile accident case to court. The case is fairly straight forward, the only question is how big the award for damages should be. He figures the case is worth maybe five grand. The JURY returns an award of $26,000.

There are unscrupulous people in all professions. Lawyers get picked on, I think, because their actions in court are a matter of public record.

Stop reading the newspaper, you'll feel better.

Musketeers

What isn't mentioned is bullet velocity. It is very high. Geneva convention outlawed mushroom bullets (because to the huge wounds they caused?). Mushroom bullets, otherwise known as hollowpoints, expand on impact, tending to cause the bullet to remain in the body and causing massive damage, instead of just going straight on through. Hollowpoints are called that because the tip of the bullet has been cut off and a small hole is drilled in the tip.

Hunter's use hollow point bullets. Warriors use ball ammo (ball just means it isn't hollow point, the bullets are still bullet shaped, not ball shaped).

I don't know what we they were thinking when the developed the 223. It uses a very small (basically the same caliber as a 22), light bullet fired at extremely high velocity. Typical high powered rifle bullet leaves the muzzle at 2500 fps. I don't know how much faster the 223 is. Anyway, the combination of very high velocity and very light bullet makes it very susecptable to interference. Hitting a leaf will cause it to start tumbling. Hitting a body will cause the same effect. Which gives you the same result as a hollow point bullet. So we got around the Geneva convention.

Maximum effective range for a 30-06 (WW I & II standard infantry caliber): 1000 yards. Not all guns are accurate at this range, but they still pack a leathal punch at that range. But they are heavier than the M-16 and the bullets are heavier.

Biggish weekend

Took Johnny to see "Blast" (a Broadway musical) Friday night in downtown Portland. Quite a show. All trumpets and drums and juggling and clowning around. Whenever I used to see drum and bugle corps in parades, I always thought they were a little weak, not enough drumming, not enough horn playing, not loud enough. This show is what a drum & bugle corp should be!

Saturday I spent fixing broken do-dads around the house. The fan in the basement fireplace had quit. Took it apart and cleaned it. All it needed was a little oil in the bearings. Upstairs smoke detector had been beeping, so I changed the battery, but it still beeped, so I unplugged it. Finally got around to checking the power and it was fine. Plugged it back and now it's working fine. Went to home depot and bought a new motion detector for the front door light. Motion detector by itself was $20. But a light fixture that incorporates a motion detector only costs $10. So I bought the light fixture and removed the lights and installed it and now the front door light doesn't stay on all night long anymore.

Sunday afternoon Ross & I drove down to Canby to visit Pat's Acres, a go-kart track. They were having races, charged us $3 admission each. We stayed and watched three races. Started with little kids, like first graders, and worked up to big kids and adults. Ross wants to build a cart. We saw some new ones for sale: $3500 to $5500. All new and shiny blue and gold anodized aluminum. Nothing mickey mouse about these karts. Some of the participants there are really into it, they have big enclosed trailers they tow behind their motor homes. Most people operate on my scale: out of the back of a pickup truck. We'll have to scrounge around on E-bay, see it we can find an old one we can fix up.