The cheapest really is best!

After many tiring trials of snapping pieces one type of wood after another, finally success. As you can see from the pictures, I finally found a type of wood that would be durable, yet springy enough to be steamed into shape. And I found it at that haven of bad lumber, the Home Depot.

There just happens to be a HD about 2 miles from the house. So many time have I gone there just to get one piece of mediocre lumber to do some project with only to be disappointed even with my expectations set so low. Oh no, even the kiln dried premium pine boards are usually either chipped to ruination or soaking wet, or both. But this time, that shortcoming became a blessing.

I went and got a nice 2X6 of green douglas fir that only had one large knot in it at the end. This board was so wet it weighed more than if it was oak. I mean, when I held it too tight, water would run between my fingers as it was squeezed out. And it was only $5! That 4/4 piece of eucalyptis, in comparison, was $50. Twice the lumber at a tenth of the price. My only thought was "Perfect!"

In all my previous attempts with different hardwoods, from exotic to local, after they had split while being bent on, examination showed that the center wasn't even warm, never mind wet and hot. The outside was plenty of both, but that condition didn't seem to penetrate more than an 1/8 inch to the interior of the piece. They all seemed either too dense or too dry to be more than a little influenced, even after being subjected to 10s of pounds of steam.

This time I knew I had a winner when it was bending under it's own weight as it went through the saw. Once I had it planed down to size I had to hold it in the middle to keep it from bending over. It probably would have gone on cold, but I already had the boiler going so it got the steam treatment.

I was doubly lucky that my brother-in-law was in town this week since even with the steam it was a two man job clamping everthing in place. Plus he had his nice camera with him and he was able to get these nice shots of the chine logs bent on.

Those of you who are very observant may have noticed that frame 11 is not there, and you'd be right. While I was cutting the notches for the chine logs, I realized it was imposible for me to predict the actual twist and bend they would take in order to cut a notch for that frame. Also, I has been occuring to me, however slowly, that the boat is a tad over built, so one less frame wouldn't matter much. And lastly, the bow will now take a more organic curve that it would have if I had left the frame in place. So it's gone. If I think it needs some additional support, I'll steam fit a strap in after it's planked.

So there you go. Now that I have identified the type of wood that I'll be using, I'll make some real progress. You can really start to get a sense of the shape of things with the fore logs in place. I'm off this afternoon to see if I can find some more lumber.

A Technical Interlude

I thought to take a break from the Stirling Model Saga and put forward an idea I've been playing around with since I started this steam engine thing, the rotary valve. The current incarnation of this idea is what the video is about.

I've always disliked the concept of reciprocation. Whether it's quid pro quo or the internal combustion engine, reciprocating bodies always seem so inelegant. Better to think that what goes around comes around. That's more my style. Laissez les bon temps rouler! I mean don't get me wrong, I like rocker arms as much as the next guy, especially really big ones, but they seem a bit primitive. Some guys fall for the roar of a big V8 humming at 4k rpm. I only hear the rattle of a thousand little bits shaking themselves loose as they suck energy out of the system. Now the high pitched whine of a gas turbine, Mmmmm-mm. Yummy! Pass the exhaust though a heat exchanger and use the waste heat to run an ammonia chiller and I'm orgasmic! Well, for now I must content myself with pistons for my engine, but that doesn't mean that I need to have everything reciprocating.

The design that you all saw in the last movie I posted had not only 6 cylinders and pistons, but each cylinder had its own valve that controls the timing of the steam going in and out of the cylinder. On top of that, each valve was to be connected to a Stevenson linkage in a circular configuration that would work to reverse the engine as needed. Not only is that a whole lot of fiddly bits to make, but each is another point of failure. And not failure as in stall out, or even grind to a stop. No, a failure of any of those little parts would be catastrophic, as in instant seizure followed by an explosion of 350 degree steam right into the passenger area.

So I'm thinking that's not so good. I mean, think of the screaming. It would be a major bother. I would probably have to feign some kind of concern and sympathy for the vict.. I mean passengers, and you know how exhausting that is. It would be a major buzz kill. Besides, what if that steam should just happen to be directed at one of the coolers. The steam might flip open the lid, melt the ice and warm the beer. Not a show stopper, but since I'd be stranded in the middle of whatever body of water I'd happen to have been traversing, it would be nice to have a cold one to pass the time until I drifted into land or drowned. It would be a drag.

So in the interest of a refreshing beverage, I came up with the gizmo in the video. If you want to put it in relation to the last video, imagine the above to be in the front and center of the engine. Blah blah blah. I just deleted a long winded explanation of how the thing works. For those of you interested, watch the video, and heres a picture of the control disk. If you're really interested in how it works, let me know and I'll put it in the comments. Otherwise, let it suffice to say that this valve gets rid of a lot of hassle and a lot of the little bitty parts and makes me feel a little more at ease about placing my coolers close to the engine.

This arraingement doesn't have a provision for reversing built in so I thought I would build a seperate valve that would redirect the steam and exhaust to alternate ports. I'm also toying with the idea of tapering the delivery arc to correspond to their angular position in the power cycle so that they only have a full pipe of steam from say 80 to 100 degrees on the stroke. I would like to leave the exhaust arc fully open throughout the stroke but as the reversing valve could send it to either arc depending on intent, both arc would need the taper.

If any of you are experienced steam enthusiasts, or are just some smarty pants and can think of a reason this wouldn't work, please let me know. It would be a major drag to go through the motions of building this thing only to have to rip it out and put together a more conventional design.

It's So Small, or My Recurring Nightmare

Shame on all of you who thought the title referred to my anatomy. Now that we've gotten the prurient out of the way we can return to our regularly scheduled rant. The object that was so tiny was every piece of this little Stirling engine that I have been trying to put together. Every time I laid out another piece onto the supplied stock, I found myself second guessing every mark. Each one was smaller than the last.

For example, one of the pieces was to make a 3mm nut out of a piece of 5mm X 10MM hexagonal stock. I am sure there are machines out there that make those as I've purchased them for 3 cents each at the hardware store. I, on the other hand, have nothing remotely that fine in terms of machinery. I could cut it out by hand, sure, but like I said, 3 cents each. There was no way I was going to spend hours trying to etch out a single nut by hand. My time isn't worth much these days, but its got be worth at least a little more than that. That kind of model work is way more fetishistic that even I can manage. Needless to say, I used the store bought.

Or rather, I didn't. I used a 6-32 nut instead. Wha-Whaat! That's right, 6-32, and 8-32 and even 10-32. All decidedly non-metric sizes. This is where I can pick up from the last post.

So, despite all obstacles I started to make all of these parts. For the holes, I found the nearest wire gauge bits. For all of the outer cuts, I turned them down to the nearest .001". Once all of the parts were made, I began to apply the threads. My local hardware store, West Trenton Hardware, is most excellent and had a fine selection of metric taps and dies. Things where looking good. I was going to get this thing together on time.

There's that time constraint that I dropped into the last post. Allow me to explain. My daughter attends Villa Victoria Academy, a local catholic girls school run by the Sisters Philipini. It's no local parish school, but a hard core convent-prep. And it has actual old school, Sound of Music nuns running it. For those of you who were blessed with a catholic education and were, like me, rebellious in nature, can appreciate the fear that they can engender. I've been in some scary places and tight situations, but nothing makes my palms sweat like the penetrating gaze only a nun can give. It makes the ruler wounds on my knuckles itch just thinking about it.

SO, it seems that three weeks ago, I promised one of the nuns who was interested in my work with small engines that I would have it done in one week, just in time for the next meeting of the Young Engineers Club so all the girls there could see what engineering was about, and ask questions of the genius builder of this awesome model engine. And all signs seemed to point to success. Perhaps my earnest promise to this emissary of the Lord was canceling out the mark of Cain that I wear on my forhead. Every piece was made and polished and each was taking it's thread or mating to it's surface perfectly. Soon it would all be done. I started with the smallest threads first, getting the 3mm, then the 4 mm, and then...

The dread 5mm die.

There are a few parts that required a 5mm external thread, and so, I went out and purchased a 5mm die to do the job. These parts just happened to be integral to the entire construction and operation of the model, but being largest, I left them for last. I had tapped all of the interior threads and now, with 2 hours to go until the promised time to show the nuns, I began to thread with my brand new 5mm die.

I chucked the first piece into the three jaw to hold it, got the die wrench out, picked up the still wrapped 5mm die, unwrapped it, put it into the wrench and began the operation. But something was wrong, the die wouldn't catch the piece. Could I have miscalculated the conversion to inches. I check my math. No, the conversion was correct. Perhaps I turned it wrong. I re-measured the piece. That was correct as well. Perhaps I wasn't applying enough pressure. I arranged the lathe carrage to press on the die and turned the chuck. Still nothing.

By now the sweat was pouring from my temples. Everything was right, but the thread wouldn't take. I was running out of time. I had hoped for at least an hour for adjustments before I had to leave, but now it was looking more like I'd have 15 minutes. I went through all of my other dies, to make sure I hadn't mounted the 4mm by mistake. Then I thought, I don't know how or why, but I thought to check the size of the die in the wrench.

4.5 mm!!

That was impossible. I retrieved the package I had just torn it from out of the trash. Had I bought the wrong one. Was it just dumb luck that would cause me to once again in my life, face the scorn of disappointed nuns. But no, the package clearly stated "5mm". There was no mistake. Here was the proof that God hates me. What are the chances that I would buy a mis-labeled die that just happened to be the keystone to my repuation as an engine builder?! I mean really, it couldn't be the 3 mis-labeled as a 4? I would have been able to correct that weeks ago. No, it had to be the very last thing.

But wait, there was still time. I had an hour. I could run down to the hardware store and still only be maybe a half hour late. Will I make it?Tune in next post to see if I was the belle of the Young Engineers Club ball, or if I was a goat, not even worth a sneer.

The 5mm Die, or Why I hate the metric system!!!

Last November I bought a lathe/mill combo machine tool from Grizzly tools. I know that it's Chinese made. Believe me, I would have far preferred to buy American, if an American company made such a thing, which to my knowledge, none does. The provenance of my tool is not the issue here and it's quality is adequate for my needs. No, what this post is about it is the little kit that I bought with my tool.

When making my purchase, I came across a little kit for a model Stirling engine. It seemed a perfect companion and a great first project. I've always had a soft spot for the Stirling and I figured it would be a good idea if I put something together first that I didn't have to trust me life too. That way I could hone my skills prior to building something that could potentially kill me (or at least horribly maim and disfigure me) if it malfunctioned. Only time would prove just how misguided my actions were that day.

The kit came in a box that was about a foot square and 4 inches deep. In actuality I later found out that the box was .35 X .35 X .1 meters, and would be my personal portal to the 2.54th level of hell.

Inside the box was a pamphlet that contained the drawings and the requisite legal mumbo with warning about how fire is hot and how tooled metal is sharp, etc. Pretty straight forward stuff. I had opened it the day I brought it home, before I had even set up the machine, glanced at the myriad tiny parts, and quickly put it somewhere safe and out of the way while I complete a few other projects.

Around the new year, most of the big things I was doing were done and as the winter was getting on in earnest, I decided to revisit the Stirling. I pulled off the shelf where it had lain dormant and took out the drawings. Having made the mistake of plunging heedlessly into things in the past, I figured I would be the height of prudence and familiarize myself with all of the drawings before taking all of the metal stock out of the shrink wrap that was keeping them contained. That was when I got my first shock. All of the measurements where in millimeters.

To most of you that may not seem like much. Give them an inch and they'll take a meter, you say? But when you're trying to put together precision components, like a shaft and bearing, especially one that needs to be air tight, the difference between 1/8" and 3mm might as well be measured in parsecs.

Now normally, switching between one system or the other is not a big deal. I'm familiar with metric measures from my studies of the physical sciences. Since academia is notoriously filled with Euro loving commie pinko milquetoasts, you'd be as likely to find a problem using yards, slugs and stone in a physics class as you would be of finding a shaved leg in a womyn's studies class. But the contents of my brain wasn't the issue, the calibration of my tools was.

How many cups in a liter? (It's 4.2267528377) If you had to measure out one liter of water, but your only tools were standard US measuring cups, how close would you get? If you're tolerance was +/- .3l you'd be in the clear. But what if you're tolerance what +/- .003l. That means you'd need to get in the range of 4.223 - 2.229. Think you could do it on you're first try? That was the problem I faced. All of my measuring equipment is marked in fractions of an inch. For outer cuts, no big deal. I can get down to a thousandth of an inch, about the width of a piece of hair (head hair that is, or a red carpet fiber if you catch my drift.) But tell me how you make a 3mm hole (+/- .05mm) without a 3mm drill bit? I'm serious, if you know, I'd love to hear it because I honestly don't know.

Now this could be the case where experience would conquer book learning, but I don't think so. There is no way to make such a precise hole that small without a tool exactly that size. So why don't I quit my belly aching and just buy some metric drill bits? I tried. I swear I did. But I ran out of time.

WTF?! you say. I read all that and there was no mention of a time constraint! And what about the 5mm die? Well this post has gone on too long, so for answers to these and other pressing questions, you'll have to wait until the next post.

Dude, Where have you been?

This is what's known as a teaser. I know it's been a long time since I last wrote in this space, and it has been a sore spot for some of my loyal readers. But I say, despair no more, I am at this moment preparing several exciting posts that detail what's been happening in steam design and building. So little to tell, so much time to tell it in. Wait, strike that, and reverse it.

I have actually been undertaking three simultaneous projects (four if you include job hunting), plus I've been doing a bit of a re-think about the slide valve arrangement for the new engine. So stay tuned!!

No Koalas Where Harmed in the Making of THIS Steamboat... yet.

I recently stopped by at my local specialty woods supplier, Willard Brothers in Lawrenceville looking for some green or air dried oak for the chine logs. Why, you might ask? Well, I've been trying to steam bend some of the kiln dried that I have from the frames and have met with limited success. It seems that the maximum size that bends the way I want it about 1/4 in. Any thicker and it seems that the steam doesn't penetrate deep enough. On second thought, it might not be working even at a 1/4 in as I have a batten that I've been using to shape the frame ends to prepare them for the log and I've been bending it dry and cold without a problem.

So the kiln dried stuff is not so good for bending, but the only air dried oak they had was in the form of 4X10 10' slabs. That's about the roughest of rough hewn timber. Any less milling and it still has leaves on it. I breifly considered getting one and cutting it down myself, but I am far from set up to handle that kind of work, particularly since my only help is an 8 year old. Not so good for muscling around a few hundred pounds of wood through power saws.

While I was wandering around the showroom contemplating just how hard it would be to cut these giant logs I noticed some lumber that looked like pale mahogany. Now mahogany takes a bend wonderfully, doesn't rot, and is perfect for boats, but and also puts a wonderful dent in any budget. But considering I only needed a little bit, I inquired after this "White Mahogany".

When I mentioned White Mahogany to the guys at the shop, they looked at me with the pitying gaze usually reserved for the mentally deficient. Finally, one said, "Oh, you mean the Eucalyptus." Probably like may of you, I've only seen eucalyptus on nature shows while it was covered in koalas, and since the focus is always on those vicious marsupials the only parts of the tree I've ever seen was the twiggy bits with the leaves. Apparently, there is more to these trees than koala food.

The variety I was admiring is called eucalyptus grandis and is a fast growing tropical hardwood which is currently being farmed on large scale in Central and South America. Now before, I get any comments, no I haven't researched the economic or environmental impact of this farming, but common sense tells me its got to be better than burning the rain forest down to make room for cattle or soybeans. Besides, its beautiful wood. Straight tight grain and light weight. and best of all, it's cheap. I don't think I'll be planking with it since it's a little more expensive than cyprus which is my next choice, but if it behaves well, I might consider it.

So I got an 11' board. I haven't had a chance to cut it to size yet but I will this week. There's enough to do the chines on both sides, plus a little left over that I'll probably shape into battens for shaping the planking.