2007-01-13

The Mistakes I've Made

Here's a list of things I've done wrong while getting started as an amateur machinist. If you're a professional, then enjoy the laugh. If you've already done these, then feel free to commiserate. If you've wound up at this page while doing research before starting, read carefully.

I bought myself a 3 in 1 combination machine: mill, drill, and lathe. It has some fairly impressive specs, the 16" swing being one of them. I figured "hey, with a swing like that, I might even be able to turn my own brake rotors." It didn't occur to me that the cutting speed near the outside of a 16" diameter disk would be scorching fast, even at the slowest speed I can turn the work. Another thing I learned is that having the cutter that far away from the lathe bed is a great way to introduce chatter. Chatter is the worst enemy of an amateur machinist using cheap Chinese tools.

So, lesson 1: read the specs carefully and understand what they mean. Bigger numbers are not necessarily better. I spend almost all of my lathe time an inch or so from the chuck. Sure, it's nice to have the capacity if I need it but most of the time it is a serious liability. A small machine with big specs equals flex. Flex equals chatter. Now, chatter is manageable so don't think my tools are useless; it's just that I didn't quite get what I was expecting.

Lesson 2 is about carbide. When I first started, I thought, "all those cutting angles are just confusing; I'll buy carbide cutters and be done with it." You guessed it, that was another mistake. First, carbide may be really hard but that makes it brittle. If you make a mistake, say by turning the work backwards by hand while the cutter is rubbing against it, or feeding the cutter into the work the wrong way, you will chip or flake the carbide. This ruins the cutting edge. Most times, this ruins the whole cutter. Carbide cutters are unforgiving; this is not a good thing for beginners. The second thing I learned about carbide is that while it holds an edge better than HHS, it isn't as sharp. Also, many carbide cutters are designed with negative rakes. These two things are a real problem with light machines where you need to worry a lot about chatter. It takes a powerful and rigid machine to exploit the benefits of carbide; even a poorly ground and sharpened HSS cutter works much better on my machine. Better yet, when I screw up, I don't waste the cutter; worst case, I have to resharpen. I still do that a lot.

Lesson 3 is that while my machine can hold 1/2" cutters, this does not mean I should buy 1/2" HSS blanks. This is another capacity verses common sense thing that I seemed to have missed when I started out. First, with my machine the flex of the actual cutter is insignificant; I don't have the power or rigidity. Properly supported, a 1/4" or 3/8" cutter is just fine. Please realise this is not about cost; the cost of a larger cutter is only marginally higher than the smaller ones. If you want to know why smaller is better, go try to grind the relief angles into 1/2" of HSS. Remember, don't grind too fast or it will overheat and loose it's HSS properties. Grind, grind, grind, grind... HSS is HARD... grind, grind, grind, grind. Now, repeat for the different shape cutters you will need. Grinding various shapes into smaller cutters is much easier, and they work just as well.

Lesson 4 is about milling - and specs. My machine is "capable" of cutting with a 3/4" endmill, or so the documentation says. So, being the kind of guy that I am, I went out and bought 3/4" endmills. You guessed it, chatter was a significant problem and I couldn't find any speed/feed combination that would settle it down. One day, I had to mill a 1/2" slot. With the 1/2" endmill in place, my little machine cut like a dream. What little chatter there was cleared right up by increasing the feed rate. I can cut a given amount of material much faster with a 1/2" endmill than I can with a 3/4" one. Bigger is not always better, at least on a small machine.

Lesson 5 is that "amateur" means "not making money." In the world of professional machining, time is money. The best machinist is the one that spends the least amount of time removing the most amount of metal, while leaving precisely the right amount behind with the right finish. Because of this, all the speed and feed charts are maximum safe starting speeds, which professionals then exceed to whatever their particular task will bear. For us hobby people, there really isn't that kind of rush so it's okay to go slower. With some materials, cutting faster will give a better finish but most times going faster just leads to more mistakes. Over the last while, I've tended to slow down the speeds as this gives me more control over the feed rates. After all, it's the machining that I enjoy more than the final product. People ask my what I make with all my tools, I tell them: swarf.

Lesson 6 is about reading. All the tools in the world will not make your metal into the right shape. You have to know how to hold it down, how to make the cut, and how to put it all together. Machining is partly about the tools, but being a machinist, amateur or otherwise, is a learned skill. But, you're here reading this so you probably already know that.

Lesson 7 is about precision. Cabinet makers and house framers both make things out of wood but they work to different levels of precision. Working with metal is like that too. Most of the stuff you read on metalworking will be from people telling you how to do things right: precisely and correctly. However, if you're making a cart axle and just want to turn down a steel rod so the wheels you have will fit over, then if you can safely get the pointy end of a cutter near the spinning rod, it will probably be good enough. Sometimes, I like to put a lot of effort into making a part more precisely than is actually necessary. I know it's a waste of time but I'm using a non-critical part as a learning exercise. If I'm off, it's no big deal as the part will still work. I'm doing it as a learning exercise because I enjoy it; I'm still not very good at it, but I enjoy it. However, when you're making something to a rough fit, you don't have to worry about it unless you want to.

Lesson 8: The more power tools I have, the more I appreciate a good hacksaw and file. It amazes me how much I can get done with basic hand tools; it also amazes me how long it takes to get a machine set up to make even a simple cut. I've learned, over the years, that if I need to get something done, and there's not too much metal to remove, it is often faster to hack it to shape and then file it smooth. I mean, I like my power tools but there are times when getting the work held down properly for a cut, at the correct angle and in the correct place, takes way longer than clamping the thing in a vice and having at it. The more you use a hacksaw or file, the better you will get at it, and the faster you will be able to shape metal. Sometimes, the simple things are the right tools for the job.

So, if you are looking to get into amateur machining, here are my recommendations:
  • Get the right machine for what you will spend the most time doing.
  • Remember that bigger specs on smaller machines means, in all likelihood, more chatter.
  • Start with HSS cutters; try carbide after you know what you're doing.
  • Avoid running your machines at maximum capacity. Their "maximum" is probably a sales pitch.
  • You don't need to run at the maximum speed and feed.
  • Learn as much as you can about techniques.
  • Be as precise as you want to be and not necessarily as precise as you've read about.
  • Don't get belligerent about using a machine when hand tools can do a better job.

Oh, and one more thing: don't forget to have fun!

Drug Philosophy

Ask drunk or stoned people if they’re having a good time and they’ll probably answer “yes,” but are they? Being high, maybe their judgement is impaired, maybe they’re not actually having a good time, maybe they just think they are. Looking at them, being all smiles and laughs, they seem to be having a good time, but they’re not actually doing anything interesting. Does being high make boring activities fun and interesting or does it impair people’s judgement such that they think boring activities are fun? Does the drug impair judgement or stimulate the brain’s pleasure centre? But then, perhaps stimulating the pleasure centre is impairing judgement. After all, there’s nothing going on that someone could judge as pleasurable, other than taking the drug. Does taking a drug to falsely stimulate the brain’s pleasure centre constitute, in itself, a good time: is that enough? Well, that depends on what a good time actually is.

Why do humans have good times? Why do we feel pleasure or pain, good or bad? Ultimately, a biologist would say we have these experiences because they guide us to behave in ways that will increase the likelihood our genes will make it into succeeding generations. In other words, we enjoy sex because that’s how we make the next generation. Along the same lines, we feel bad when we hurt someone because if our society fails, odds are the babies we made won’t be able to grow to have their own babies. It’s a pretty simplified way of looking at it but the general idea is that good or bad times provide us with guides to living productively, to prosper in our society, genetically speaking.

Given that good times are natural rewards for making good decision, what then of taking drugs? Well, how would taking drugs help people make better decisions? Obviously, the answer is that it doesn’t; drugs impair the ability to make good decisions, they don’t help. Drugs bypass a natural system of guidance; they only reward people for taking drugs, nothing more, nothing useful. They make taking drugs good and not taking drugs bad. It even alters the natural balance of feeling and swamps out any real feel-good rewards, and this further degrades the natural system which then leaves people without useful tools for managing their lives. Being high is not feeling good, it’s not the same as having a good time, it’s just being high. Drunk or stoned people aren’t having a good time; they may think they are, but they’re wrong, their impaired brains are deceiving them. Small wonder heavy drug users have such messed up lives.


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2007-01-01

Arcade Philosophy:

Philosophy can be grossly divided into two different camps: the mechanistic belief that reality is as observed and the belief that something more exists. The observable reality system requires no explanation but does leave people devoid of purpose. Is there nothing more to life than propagating genes and, possibly, the pursuit of happiness? Throughout the ages, people have created a multitude of systems that create purpose by adding unobservable elements to reality: Gods, destiny and providence, divine justice, the list goes on. This paper offers yet another enhanced-reality concept. While somewhat humorous, it does a better job of explaining the human predicament than most other enhanced-reality theories.

If the world is not as we can observe it, and something more - supernatural - exists, then we might as well go all the way and state that we exist in a virtual reality environment where everything is an illusion. Nothing we observe really exists. Our world, the universe, and our very existence is a creation - a secondary false-reality created for a purpose. Of course, this merely shifts the original question one reality up - what purpose does the creating reality have? However, the answer to that cannot be observed from this false reality. Thus, we can leave that question to our creators. The question we can pursue is: why did they create us?

To understand the motives of these creators, we can project our own lives into the future, millions or perhaps even billions of years. With sufficient time to evolve, it is clear that death will become optional and eternal life the norm. Technology would offer no limitations that we can imagine. With, what would seem to us, near unlimited power and immortality, what would there be to do? In such a situation, how would we entertain ourselves? Well, we would probably play games and watch entertaining things.

What games would bored and nearly-omnipotent beings partake in? Perhaps they would be drawn to the carnival, the thrills of wild rides that offer fear without true risk. What would an immortal being be afraid of the most? Death, of course. The fear of death - the one constant feature of our reality. From a very young age, we learn that we are going to die, the people we love are going to die, that everyone is going to die. We fear disease, famine, war, accident, and violence. Yes, there are places on this planet that offer relative safety compared to other more dangerous areas. Carnivals also have a kiddie section with easy not-too-scary rides. Our reality also offers a choice between the relaxed and intense, between the tilt-a-whirl and the roller coaster. Every ride, easy or wild, offers the same fear of death. The only real change is in immediacy.

What entertainment would such beings enjoy? Reality shows perhaps? Maybe they would enjoy watching ignorant characters attempt to discover their place in this virtual reality: to invent gods or attempt to build rational explanations. This would be great fun, learning the latest antics, theories, or worship. It would be especially fun to inject odd events that the inhabitants would have to build explanations for. Perhaps a messiah, or an odd physics result. The bizarre world of quantum mechanics could easily be explained as just a joke on our poor physicists, religion as just a joke on all of us.

If you suppose that the reality we exist in is not as it seems, and that something supernatural need exist, then a casual observation of this reality leads to one truly obvious conclusion. We exist in a virtual reality game - World of Earth - where each of us is a character. We have souls, those eternal beings that guide our characters through this environment. We eventual die, as is our destiny, and our souls get to experience a thrilling fear of death, without any real risk. It is a popular game, at six billion characters and counting, and it must also be very entertaining to watch from the outside. I wonder what kind of ratings we're getting?