Plans, projects and how-to's for home machinists

MachinistBlog.com is 2 years old

By Rob on January 11, 2011

No, traffic didn't suddenly drop off. That last point only shows our hits for the first week of January.

January 6th was the second anniversary of MachinistBlog.com. I’m not usually one to brag but I am proud of this achievement. Almost everyone who starts a blog quits within a few months, or even a few days, after they find out how much work it is to keep creating content for one. When I started out I thought it would be easy to write at least one article each day. I was very wrong and quickly decided that one article per week, on the average, would be a more reasonable goal for someone with a family, a full-time job and some other interests. I’m not going to claim that what I write is well-written or very interesting, but for two years now I’ve been regularly adding new content to the web site. But I have had a lot of help and I owe a lot of thanks to these people:

My wife, for putting up with me and my hobbies.

Nate, who has been my copy editor from almost the beginning. He has greatly improved my writing by patiently and gently pointing out my errors. He’s also written some of our most popular and interesting articles even though he’s not a machinist.

Mikey, who really should be the one with a blog. He’s a much more experienced machinist with excellent writing and teaching skills. Mikey has contributed articles, he’s been very supportive and he’s given me some excellent advice.

Earl, Bick, Bogs, Pat, Ralph and Steve (coming soon), who have contributed articles and other material. I owe a lot, and I think we all do, to them and others like them who are willing to share their knowledge and help others learn.

All of you who have visited this web site. I don’t earn any money from MachinistBlog.com. Most of the reward I get is from watching its popularity grow and learning we’ve helped someone or taught them something.

Future Plans and Challenges

It’s been getting harder to meet my goal of writing one new article each week because the things I want to write about lately require more time and preparation.

I hope to create my first YouTube video soon. It’s going to require learning some new skills and overcoming my natural desire to achieve perfection, which often gets in the way of getting things finished.

I’d like to do more photo essays and tutorials. But first I’ve got to buy some lighting equipment because my camera’s flash is too harsh and directional. I think I need an umbrella light but I’ve never used one and I don’t know what to buy. If you can offer me any advice I’d appreciate it.

I’d also like to get the forum going more. I’m not trying to compete with the more established ones but I would like it to have enough users so we can get some discussions going. I chose the forum software we’re using because it’s the only one that integrates completely with WordPress, but I’m a concerned that it might be a little difficult to read and use. Again, I’d appreciate any suggestions or feedback you have.

I’ve had an itch to spend more time in my workshop

By Rob on October 12, 2010

Yes, I know. I haven’t added much new material to MachinistBlog.com lately. If it weren’t for Mike and Nate this web site would be as stale as 3-week old bread. The reason is that I’ve had a strong itch to spend as much time as I can in my workshop before I get busy with getting our yard, gardens and house ready for winter. My list of chores includes spending at least 20 hours picking up our leaves. I have an arsenal of gas and electric powered tools to help, but even so I’m often too tired or too cold when I finish for the night to machine metal.

It has nothing to do with metalworking but I want to tell you about my next-door neighbor who thinks it’s OK for her to blow her leaves into our yard. It’s not by accident. She’ll stand there and patiently use her leaf blower to push her leaves through a chain-link fence into my backyard. I’m not sure why, but apparently she must think that the leaves that fall from my trees into her yard should be my problem not hers, and so should most of the leaves from her trees, along with anybody else’s leaves that blow into her yard.

She must not have noticed, or cares, that she is upwind of me and I get many more leaves from her trees than she gets from mine. The only leaves she got from my trees were the ones that fell on windless days from branches that hung over her yard. And now she doesn’t even get those, because she had my tree limbs, and all the other neighbor’s, cut off at her property line.

I can be very assertive but I don’t think it is smart to feud with a neighbor. So I quietly put up with her for years. But, a few years ago she was being particularly brazen about it so I called the police. I was then surprised to find out there is no law against blowing your leaves into somebody else’s yard!

The police officer did change her behavior a little. Instead of blowing her leaves directly into my yard she started leaving them in the front yard near the property line, where there is no fence, so the wind would do her dirty work for her. And last year her new husband tried something different. He blew the leaves out into rush hour traffic so the breeze from the cars would carry them down the road. Most of them ended up in my yard, but some of the other neighbors got a chance to share some of the joy also.

Getting back to my workshop, I haven’t been doing much machining even though I’ve been spending a lot of time in it. Instead, I’ve been concentrating on making more room in my shop by reorganizing it and ruthlessly getting rid of stuff that I don’t need or have no room for.

I don’t want to give anyone the impression that you need a lot of space to have a home machine shop. You don’t, and for a long time mine only took up an 8×10-foot space in the back of our single-car garage. But I’ve recently added a CNC mini-mill (used) that came in a large wooden enclosure, another lathe (a used 8×12 that I got a good deal on), and a 4×6 horizontal bandsaw (also used). In addition, I already had a full-size table saw, a bandsaw, a large combination sander, bicycles, an outboard motor and some assorted yard tools. It was crowded, although not as bad as you may think because most of my larger tools are mounted on wheels so I can store them out of the way when I’m not using them.

I do have one machining project I’m actively working on. It’s HMEM’s EZ Build engine. I invited a friend to come over and learn how to machine metal and I though it would be a good project for him to work on. I also thought I should build one myself first. So I put Jan Ridders’ ‘Simpler’ Stirling engine on hold again to do that.

There’s another reason why I haven’t been working on this web site much lately. I’ve been taking a 3-hour MIG welding class on Monday nights. You’ll be hearing more about that later.

- Rob

Denmark to become the fourth nation to launch a man into space?

By Rob on August 30, 2010

MachinistBlog.com is pleased to announce our support for Copenhagen Suborbitals, a small non-profit suborbital space endeavor led by two guys with big brass ones. If they are successful Denmark will become the world’s fourth nation to launch a man into space, after Russia, the United States and China. In addition to wishing them well we have donated $10 to help their efforts :-)

Seriously, I think what Kristian von Bengtson, Peter Madsen and their small group has accomplished is pretty impressive, especially on a budget that is considerably less than $100,000.

Here are the pertinent facts

Their rocket is designed for sub-orbital flight. The same kind of flight that made Alan Shephard the first American in space.

Their astronaut will have very little room to move and will be “half-sitting, half-standing,” a position they think he’ll be able to withstand because launch forces are expected to be less than 3-Gs. The first few test flights will carry a dummy that will be used to test that theory. One of those flights is expected to take place within the next couple of weeks (and very likely within the next few days).

The booster is somewhat unusual. It’s a “hybrid” because it uses both liquid and solid propellants. Liquid oxygen is used for the oxidizer but I’m not completely sure what kind of fuel it will use. I believe it’s going to be polyurethane. They’ve also tested paraffin and epoxy. (That’s right, plastic, wax and glue.)

By the way, there is a machining angle to this story. The photo below shows the booster’s graphite nozzle being made on a lathe.

Akin’s Laws of Spacecraft Design

By Rob on February 16, 2010

I’m not exactly sure who Dave Akin is, but he’s obviously a wise man. He wrote these 33 Laws of Spacecraft Design that are full of astute insights and observations that can be applied to many other engineering, design and management situations. He’s kindly granted permission for them to be reprinted, and so here they are:

1. Engineering is done with numbers. Analysis without numbers is only an opinion.

2. To design a spacecraft right takes an infinite amount of effort. This is why it’s a good idea to design them to operate when some things are wrong .

3. Design is an iterative process. The necessary number of iterations is one more than the number you have currently done. This is true at any point in time.

4. Your best design efforts will inevitably wind up being useless in the final design. Learn to live with the disappointment.

5. (Miller’s Law) Three points determine a curve.

6. (Mar’s Law) Everything is linear if plotted log-log with a fat magic marker.

7. At the start of any design effort, the person who most wants to be team leader is least likely to be capable of it.

8. In nature, the optimum is almost always in the middle somewhere. Distrust assertions that the optimum is at an extreme point.

9. Not having all the information you need is never a satisfactory excuse for not starting the analysis.

10. When in doubt, estimate. In an emergency, guess. But be sure to go back and clean up the mess when the real numbers come along.

11. Sometimes, the fastest way to get to the end is to throw everything out and start over.

12. There is never a single right solution. There are always multiple wrong ones, though.

13. Design is based on requirements. There’s no justification for designing something one bit “better” than the requirements dictate.

14. (Edison’s Law) “Better” is the enemy of “good”.

15. (Shea’s Law) The ability to improve a design occurs primarily at the interfaces. This is also the prime location for screwing it up.

16. The previous people who did a similar analysis did not have a direct pipeline to the wisdom of the ages. There is therefore no reason to believe their analysis over yours. There is especially no reason to present their analysis as yours.

17. The fact that an analysis appears in print has no relationship to the likelihood of its being correct.

18. Past experience is excellent for providing a reality check. Too much reality can doom an otherwise worthwhile design, though.

19. The odds are greatly against you being immensely smarter than everyone else in the field. If your analysis says your terminal velocity is twice the speed of light, you may have invented warp drive, but the chances are a lot better that you’ve screwed up.

20. A bad design with a good presentation is doomed eventually. A good design with a bad presentation is doomed immediately.

21. (Larrabee’s Law) Half of everything you hear in a classroom is crap. Education is figuring out which half is which.

22. When in doubt, document. (Documentation requirements will reach a maximum shortly after the termination of a program.)

23. The schedule you develop will seem like a complete work of fiction up until the time your customer fires you for not meeting it.

24. It’s called a “Work Breakdown Structure” because the Work remaining will grow until you have a Breakdown, unless you enforce some Structure on it.

25. (Bowden’s Law) Following a testing failure, it’s always possible to refine the analysis to show that you really had negative margins all along.

26. (Montemerlo’s Law) Don’t do nuthin’ dumb.

27. (Varsi’s Law) Schedules only move in one direction.

28. (Ranger’s Law) There ain’t no such thing as a free launch.

29. (von Tiesenhausen’s Law of Program Management) To get an accurate estimate of final program requirements, multiply the initial time estimates by pi, and slide the decimal point on the cost estimates one place to the right.

30. (von Tiesenhausen’s Law of Engineering Design) If you want to have a maximum effect on the design of a new engineering system, learn to draw. Engineers always wind up designing the vehicle to look like the initial artist’s concept.

31. (Mo’s Law of Evolutionary Development) You can’t get to the moon by climbing successively taller trees.

32. (Atkin’s Law of Demonstrations) When the hardware is working perfectly, the really important visitors don’t show up.

33. Space is a completely unforgiving environment. If you screw up the engineering, somebody dies (and there’s no partial credit because most of the analysis was right…)

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