I Will Beat This Thing if it Kills Me

I have been trying to rehabilitate my wayward CNC lathe. I built it in 2014, and for some reason, I quit working on it. I don’t recall the final straw, but I know that I was frustrated with the motor setup, and I was disturbed to learn that the screws that move the carriage (one of which cost a ton of money) were not adequate for good machining.

I started working on it last week, and I learned a few things.

First off, the screws aren’t that bad. The screw on the x axis (toward and away from the operator) is accurate to within a thousandth or so, which is about as good as I will ever need it to be. The other screw (z, or left and right) can be made accurate to within a couple of thousandths, which will do for 98% of hobby projects. I would be better of with ball screws, which have no significant backlash, but I don’t need them at this stage. Better to put my effort into making the motors and programs work.

Second thing: ball screws are getting cheaper and easier to find. I should be able to replace the z screw for under a hundred bucks, and the x screw, if it needs to be replaced at all, will be less.

Third thing: you don’t need a compound rest on a CNC lathe. A compound rest, for those of you who haven’t stopped reading already, is a second slide on top of the main carriage slide. The main slide, or cross slide, moves the tool toward you and away from you. The compound sits on it, and it can be swiveled, so it can move the tool in all sorts of directions in the horizontal plane.

A compound is very useful in manual machining, but with CNC, it’s a problem, unless it’s connected to a computer. The computer needs to control all movement and know where everything is, and that doesn’t happen with a compound that isn’t wired up. You have to leave it in one position all the time, so the computer knows where it is. That means it takes up space for no reason, and because compound rests are inherently wobbly, it adds error.

I took mine off and replaced it with a nice aluminum block. I was really happy with the block. It’s probably the first thing I’ve ever machined successfully, in one try, with no errors.

Now if I can just get the lathe to work.

The little flat part that projects in front of the tool post is probably not necessary, but I left it there in case I found a need to mount additional stuff. You never know.

Fourth thing: if you use a KFlop controller, like mine, you will not be able to do threading without two spindle inputs. Mach3, the program just about everyone uses, will let you observe your spindle’s movements with a single sensor that, obviously, sends a signal once every rotation. The KFlop isn’t having that, so I have to rig up a two-sensor thing.

The mini-lathe came with variable speed and a tachometer, so it has a spindle sensor already. There is a disk around the spindle at one end, and there is a hole in the disk. The disk runs through a caliper-looking thing which contains an optical sensor. Every time the hole goes through, the sensor sends a signal to the tachometer, and the lathe tells me how fast it’s going.

The CNC plans I bought say to buy a new sensor and install it on the spindle. The sensor is inductive. That must mean it has a coil in it. Anyway, you mount a small flat piece of metal on the spindle, and every time it passes the new sensor, it makes current run through the sensor, telling the controller what the spindle is doing. When I realized the lathe already had a sensor, I decided to try to hack into it and connect it to the KFlop. That’s when I found out it won’t work. Now I have to put a second disk on the spindle with two cheap optical sensors at 90 degrees to each other.

I still can’t get the software to work right. That’s largely because I made a lathe and not a mill. You have to be stupid to make a lathe, because no one does it. Because there are so few hobby CNC lathes, there are very few people who can help you with problems. Also, the people who make the KFlop do not provide computer code for two-axis machines, so you may have to learn to alter C programs to work in two dimensions.

Aggravating.

Nonetheless, things are moving right along.

I have one problem which is strictly physical, i.e., not in software. I crashed the lathe a long time ago, and now it tends to sputter. I changed the brushes on the motor, and it didn’t help. The old brushes were fine. I am now wondering if I damaged the contacts on the switch that changes the lathe from forward to reverse motion. Anyway, it’s one more thing to fix.

I bought a long piece of Delrin rod from Zoro Tools. I figured it would be more forgiving than aluminum when the lathe crashed. We’ll see. And Delrin is very useful stuff.

In other news, I am learning a lot about dementia. This week I realized that dementia is like dissection. It shows you what’s under people’s skin. It tells you what’s inside them.

My dad keeps having problems with his prescriptions, which I dole out for him, putting everything in a pill organizer. His doctor is supposed to keep them flowing to him by mail, by keeping his refills up to date. The supplier is supposed to send new pills automatically. Over and over, they screw up. I call the supplier, and they say the doctor didn’t update the prescription. I call the doctor, and they tell me to talk to the supplier. No one ever says the obvious thing, which is, “We are incompetent. Sorry. We’ll fix it.”

He ran out of one of his medications, and there was turmoil for about half an hour.

He can’t keep the names of the companies that supply his drugs straight. He can’t remember who sends the prescriptions. He became very angry and agitated, and he kept asking me the same things over and over. I was very calm about it; this is a problem that literally takes 30 seconds to fix. You make a note to call the doctor and the prescription people, and you go on with life. He kept telling me he couldn’t have this chaos in his life, and he was clearly upset that I wasn’t upset.

I had a sudden realization: he enjoys being angry and upset. It brings him pleasure. He doesn’t like to see it end. In the instant I saw that, a lot of things from my childhood started to make sense.

Most people don’t like being upset. When they get upset, they look for solutions to put an end to it. My dad never did that. When he got angry, he looked for ways to prolong it and spread it to other people. He used to get mad at people he couldn’t rattle. He thought there was something wrong with them. He had an employee he criticized for being unflappable; he found the man extremely frustrating, just because he didn’t burst into tears or share in the hysteria. I didn’t understand that. Now I do.

My house was always full of stress and yelling. When we would ask him to calm down, he always said, “Don’t tell me to calm down!” Now I see why he did that. He was enjoying himself.

You couldn’t tell him you were sorry and have an end to the problem. Even if you fixed the problem on the spot, he kept going. He didn’t stop until he got tired, and that could take hours. Sometimes he would run down and stop, and then it would start up again later. Sometimes he resumed days afterward.

I can’t believe I never saw this before.

It shows how harmful bad habits are to older people. When you’re 50 and you still have it together, you can change. When you become demented, forget it. People can’t help you with good advice, because you can’t receive it. All they can do is try to limit your suffering. And theirs. By spending less time with you.

Whatever you’re hiding from your kids today will eventually be so obvious it might as well be on a billboard.

Awareness of the problems my parents and grandparents have or had is not useless. It can’t help them, but it can help me. These things are caused or exacerbated by spirits, and those spirits leave the dead and prey on their descendants. As is so often the case, I am presented with a situation in which I can be blessed through others, yet I can’t bless them in return.

My dad’s potential to change and enjoy life is limited, and my sister is a lost cause. I don’t even know if she’s alive. The strange thing is that I’m not agitated about it. Many Christians have the idea that you’re never supposed to stop weeping and worrying over people; that’s a huge lie. We are supposed to be blessed, and you can’t be blessed if your life consists of perpetual handwringing over people who choose, habitually and over a course of decades, to harm themselves.

The Holy Spirit killed Ananias and Sapphira; people forget that. Peter spoke curses to them, and they died on the spot. He didn’t weep. He didn’t beg them to change. I’m sure he wasn’t happy about what happened to them, but the Holy Spirit tells us which battles to fight and which to drop, and he apparently chose not to have Peter wear himself out on Ananias and Sapphira.

We don’t know what people did for them in the time leading up to their deaths. They may have fasted and prayed for them every day for months.

I pray for my dad every day. I do what I can in the supernatural, and I make his life easy. That’s plenty of effort; I’m doing what I’m supposed to. Results can’t be guaranteed; I am not responsible for them. I am content.

I have more peace now that I understand what’s going on. That’s good. It’s bad when other people can’t be blessed, but I’ll take my blessings just the same.