Package structure is not something to be considered idly.
The first thing I do when I look at an application is
$ tree -d src/
And I get something like this:
| |-- dao
| |-- domain
| `-- engine
| |-- business
| |-- adapter
| |-- exception
What do I know about this application from its package structure? Not much. It has a core, an engine, that's exciting. But not at all descriptive of what it does. Sounds like a spaceship! or an alien weapon!
However, if I were building a spaceship, I'd do something like this:
OK, so a space ship is much much easier to design than a piece of software! I have all the major features described at the top level. I can tell what the ship does, what its major components are.
The ship's design is organized by Features of the ship. Not by layer or any other attribute. For example, a builder or a command isn't a feature of a piece of software. Neither is an exception, a dao, a domain, an adapter..
These are all layers or programmatic idioms. Grouping classes by layer or type is a common mistake in designing software. It is always taught that one should design by feature, not by implementation detail.
The total stroke of a Dupont toggle machine is 2x the crank offset, plus the distance between dies and the upward stroke while compressing the spring.
Little Giant sells springs, toggle links, etc for the 25,50,100# hammers.
Instead of trying to calculate which truck spring to buy, just get a complete toggle link from them. Use the same crank offset as the LG. Or use the LG crank.
I like the later LG upside-down Pitman arm.
Buying the above from LG is probably less expensive than making it all. And it would be correct the first time. No need to re-invent the whole thing.
Most of the early tire hammers used big structural tube as the frame, in place of the big sand-cast iron frames of the early 1900s power hammers.
Instead of structural tube or I-beam, use an A-frame like the Japanese power hammers. An A-frame hammer with a separate anvil can be deconstructed and moved more easily than a monolithic design. An a-frame can be made stiffer than a structural tube or beam, which will tend to develop oscillations and rocking with a small base and high center of gravity.
The recommended anvil weight ratio (from IronKiss) is 16:1.
A 6x36" bar of 1018 should weigh around 289#, but I've seen different on the scales!
7x36 would be closer to 400#, the ideal weight. For a 50# hammer, a 11" base..
Metals weight calc for dimensions.
Meh. Bow spring or coil.
These are the owners of Little Giant company. They bought the rights and tooling a few years ago to help people restore and maintain their Little Giants.
Great place to get parts even if you don't have a little giant. Almost everything but the cast frame is available. Most of the parts which were problematic have improved replacements here too.
This is an ebay auction for a strange bookmobile. It appears to have been either converted to a riot/prison van or just had some bars put in it to keep people out.
Check out those bookshelves! It would make a really cool RV.
I finally got a solar auto-dimming welding helmet last year. I never found that with proper technique these were absolutely necessary for quality welding, but they do make it possible to make all tack welds and finish welds without ever lifting your helmet. I hate welding helmets in general, and it is important to get the best ones and maintain them, because the cheap ones are just shit and make welding a pain in the ass.
The automatic helmets have some drawbacks though. You have to manually adjust the light blocking and sensitivity to the environment and type of welding. If the photovoltaic cell is obscured by something, which is often the case when working in tight places like under cars etc, the auto-dimming doesn't work, and you end up effectively looking at an arc through a #3-4 shade, when you should be protected by a #10.
More expensive helmets, which I would recommend for anyone who welds daily, have auto-sensing filter controllers for ambient light settings, arc amperage, arc time display, other nice stuff. Most of the welding helmets don't have integrated air filters. Welding fumes are toxic, sometimes deadly (galvanized plating will kill you).
The automatic helmets are a pretty recent development.
The next generation is coming though, and will be a significant improvement over the previous glass filters.
These provide a real time HDR projection directly to the eye using video and real time HDR processing:
By processing multiple video streams at different dynamic ranges and combining the optimal visible light into an optimal stream, you get complete detail of the weld area, molten metal puddle and arc without the extreme contrast that a #10 shade provides.
I pulled this little elm out of the ground a few days ago. I chopped it short and cut some of the roots. Then I put it in some "recycled organic material" plus a little nitro.. I didn't figure it'd survive, but nitro makes every plant happy. This is 1 week after planting the stump.
Writing words is in the blood. I'm the son of a journalist and accomplished author, and the brother of an accomplished author. I've been told I'm a good writer, then a bad writer. For example, the entrance exam at a community college scored me very low on the essay portion, due to my not following the format. In fact, they scored me so low, I didn't even get into a required 101 level writing course. Bad writer. Academically speaking, I'm too informal. Maybe that doesn't count.
I found this simple script that removes wordiness from text by removing or simplifying words and phrases.
The V8 in the 500SEC (Mercedes M117 engine, 5.0 liter) is interesting. It has a forged crank, pistons, rods, light but stiff aluminum block and heads, double row timing chain, some other interesting bits for that time. OHC, 2 valve per cylinder, and like most benz engines have stainless valves with the exhaust valves sodium filled, hardened seats, polished ports, internally balanced and factory cc'd.
They do have a serious flaw though. The SOHC heads require a very long, very heavy timing chain, which is common on German cars of the 'investment' grade, which drives the valve and ignition timing. The chain is guided and tensioned by a number of plastic guide rails. These are consumable items, since they are friction surfaces, subjected to wear by having a heavy steel chain under tension dragged over them at 1/2 the engine's RPM. I've seen some worn through to the aluminum backing underneath, which means bits of aluminum and plastic have ground off into the sump, and that the timing is waay off, chain probably wearing badly, etc.
This would be a problem on engines with bad cam oilers, bad chain tensioners, people not getting oil changes, bad/wrong oil, other simple things like that which shouldn't happen to a well maintained car. However, these were built more than 25 years ago, and nobody knew then how long the engines would be used or what time and chemical breakdown would do to the plastic guide rails.
BTW I don't think anyone had trouble with the rails in the 80s, not at least like they did with the weak single row timing chain on the 380 engines, which was later replaced with the double row chain.
Long story short, the guide rails will get brittle and break off, fall down into the timing cover and get stuck between the chain and teeth of a cog. This will destroy the engine beyond any reasonable repair, as the timing chain can jump a few teeth, break, or otherwise cause valve/piston interference, after which you will have nothing left but a block that may be salvageable.
In the above picture, the front timing cover is off, exposing the crank timing sprocket, idler, tensioner (left side) upper guides (white plastic sticking out of the heads). This engine has been conveniently pulled out of the car..
I think the labor on changing out all of the guide rails (at a good mechanic) will come to around $7k, plus all of the "While you're in there" shit that you'll want done, somewhere around $9k.
I didn't have any power problems or slapping noise at startup, or any indication that there was anything wrong with the engine except that I hadn't actually opened it up to take a look. That could have been a bad engine blowing mistake.
This is where it pays to know what you're getting into when you buy a used car. Know EVERYTHING about it. Become an expert in that model before you buy it so that you know what to ask, what to look for, how much it will cost to fix (time+money), whether or not you can drive it or have to trailer it home.
The above sequence shows what the guide rails look like when they've failed. It just broke in half, one half of which is bumping around down there on the ignition sprocket, just waiting to get chewed under..
A new set of guide rails (upper only) costs about $18, and they're white as the driven snow, unlike this one, which is brownish-oil colored, indicating it's chemically transformed over the years into a fragile, brittle time bomb. To swap out the upper rails took about 4 hours, including the 'while your in there' shit, but without removing the front cover and getting at all the lower rails. The timing chain is showing no stretch, which is nice and unexpected, the timing gears aren't worn any more than they should be at this point.
One thing that's a concern with certain engines is one wearing part being of a dissimilar material or less wear resistant than the part wearing on it. For example the cams and sprockets are cast iron, but the chain is an alloy suitable for chains, the lifters of a hardened steel like 4150 or something even harder.
Of course all these parts are protected by a sheet of oil, but it's not a 100% friction barrier in any case.
If you are reading anything below that is missing a photo, it's because lightbox (the service) died.
I don't know why (because maybe they ran out of money?), or when it will come back on line, if ever, but until then, use your imagination?
I'll be finding some better way to take pictures and create posts automatically..
Or maybe I'll just write a little Android app that does this. I'll call it "instagramme". Billion dollard idear right thur.
Apple Mac Pro:
One 3.33GHz 6-Core Intel Xeon “Westmere”
1TB 7200-rpm Serial ATA 3Gb/s hard drive
ATI Radeon HD 5870 1GB
One 18x SuperDrive
Apple total cost: $5,060.69
Intel® Core™ i7-3930K (Six Core, 12MB Cache,Overclocked up to 3.9Ghz)
16GB Quad Channel DDR3 at 1600MHz
2GB GDDR5 AMD Radeon HD 7870
1TB SATA 6Gb/s (7,200RPM) 32MB Cache
Single Drive: 24X CD/DVD burner (DVD+/-RW) w/double layer write capability
Alienware total cost: $2,299.00
So, Alienware is supplying the same chip (Intel 3930k), RAM, disk, double the graphics memory for half of the $$. I've always considered Alienware pretty damn expensive, and now they're owned by a company which I'd avoid, but this is commodity hardware, not a laptop with durability problems.
And on top of that, buying an Apple is like driving a Priius or a VW New Beetle. You look like a fool.
It's been a while since I owned a car that went in a straight line on its own. Every car I've had pulled to the right, which is normal on a 2 lane road that is crowned to shed rain water. But if I'm on the highway on a flat surface, I should be able to cruise in a straight line without touching the wheel. The correct alignment won't scrub off the sides of tires excessively and won't pull in either direction at all. Some cars have a centering bias due to either (rarely) an automatic hydraulic balancing system (like Citroen's DIRAVI) or due to suspension geometry. Forget about DIRAVI here.
Most cars have adjustable toe/steer. The mechanical linkage which sets the L/R bias of each front wheel is infinitely (finely?) adjustable within a few inches. The slack in the steering will determine the futility of these adjustments to some degree, but lets assume there's no slack, as all ball joints and steering linkage have been renewed. Caster/Camber are not adjustable here, and the spring rate and height are fixed also.
These would be fun to play around with, but ultimately would just make things handle worse unless there was a race track to try all the infinite settings out on.
I've seen many different methods of alignment using lasers, bubble levels, strings, beams etc... the basic point is to get all 4 wheels pointing in the same direction, so that there is no scrubbing, pulling, side tracking or crabbing.
In order to properly align a car, it must be on a flat, level surface. This is the basic criteria. The rear wheels are probably not adjustable for toe. The front wheels need to be on a surface that allows them to turn freely while loaded. The expensive alignment sets I've used had heavy steel platforms with big sealed roller bearings. They slip under the wheels and and turn freely. The cheap ones are pairs of steel plates with a point on one side that allows full toe/camber/caster adjustment. Lasers are attached to the wheels and used to point at gauges in the rear, which measure toe-in and toe-out.
Before "LASERS" were invented, people used string or long beams. An old trick was to grease up the back of a pair of vinyl tiles and roll the front wheels onto these.
Here's that method in detail:
Here's a shot of a 126C Mercedes in Miami Beach, FL when it was new in 1983. This was an $80,000 car in '83 dollars. Adjusted for inflation that's $178,000 in today's money. The owner sold it to a rich young rich person, who totaled it 2 weeks later. Don't do cocaine.
Currently I have the 15x6" Mercedes 'manhole cover' aero wheels with tires that should have been replaced years ago. The wheels pictured above, Ronal R-31 Centras in 16x8 should be arriving shortly.
I changed out the engine mounts recently, next is front end suspension refresh, rear shocks, and to take a look at the differential, which is leaking and will need to be refreshed. I broke one of the front subframe bushing mounts this weekend while taking it off the jack stands. That will need re-welding, and I'll probably cut out and rebuild the area with 1/8" steel like I did on the other side.