Archive for April, 2009

The first step was to install the top brackets. Well, first had to get the proper bolts. I wanted to use 3/4″ thick (radius) by 8″ long lag bolts — galvanized to support the weather. When I built my first treehouse, I just bought them from OSH or San Lorenzo Lumber. Now a days, we have Home Depot, and still OSH. Home depot doesn’t really carry large lag bolts, and OSH has a wider selection, but no 3/4″ lag bolts. Both places have coarse thread 3/4″ ungalvanized bolts, and that was my only real option. I could order something from the internet…but I wasn’t that patient. I did some test holes in a sample tree and discovered that the coarse thread 3/4″ bolts thread quite nicely into a 5/8″ pilot hole. The only problem is that they will eventually rust, since they aren’t galvanized. I figure it will be an experiment to see how long before they rust and cause the treehouse to fall down. I think it will last at least 10 years, probably 20 and maybe 30. The bolts will be “somewhat” protected from the elements, so they shouldn’t rust all that fast. I realize I’m making a mistake by not using the proper hardware, but that’s okay by me.

So, I sunk the first bracket into the tree; all was fine. I drilled the hole for the second and realized that an 8″ lag bolt is too big for a tree that has a radius slightly less than 8″ (oh, duh!). I really need to have used a larger tree, but this is the one I wanted it in. So, I traded in my 8″ bolts for 5″ bolts. They seem to get as much holding power as the longer ones, and I think 8″ is overkill.

Rock climbers use much smaller bolts — but then again, those bolts are drilled into solid granite. So, a second experiment is to see how well these shorter ones work. Before I got the shorter ones, I used a few of the 8″ ones but made a 1″ space out off 3/4 inner diameter by 1″ outer diameter steel pipe I had from moving my mill.

Here’s some more iPhone pictures:

Each beam was carefully leveled with the previous beam and then leveled radially. Unfortunately…I now realize that didn’t work so well, as some of the old beams are slightly warped. I should have ripped (or jointed) a side perfectly flat before using them…but then again…”oh well”..

More soon…

I bought some 4” wide by 1/4” thick steel from SIMS metal in San Jose with the intent on using it to make brackets. Now, 4” would be perfect if I used 4×4s for the knee braces, which I would ideally want to use. However, I have 2×8s for free, so I’m going to use those. To create a bracket that holds them, I need 2” wide pieces of steel. At first, I figured I’d just cut the 4” pieces down to size, but I quickly discovered how hard that was to do with a sawzall or jigsaw (with metal cutting blades, of course).

So, I went back to SIMs and bought some 2” wide 1/4” stock mild steel — this is perfect for the 1.5” wide “2×8s”, since the two 1/4” sides takes up the extra 1/2”.

I took some pictures with my good camera and the iPhone. I’ll use the latter since I have them handy on my computer already. I used the mill to create 1.5” spaces out of some square tubing I had; I used them to ensure the spacing was correct when I welded the brackets together. I drilled the holes *after* welding, which was a mistake, since the top was really chattery when I drilled it. I drilled it after to ensure the holes lined up, which seemed like a good idea at the time. Instead of doing that, I now realize I could have just drilled the two sides together at the same time *before* I welded them. Oh well!

It is really tricky welding 1/4” steel with an oxy-acetylene torch. I used my dad’s old #2 or #3 tip and old torch, which leaked slightly at first and caught on fire near the handle. A quick tightening with the wrench prevented subsequent fires, and I used gloves from then on since it was super-hot welding with lots of heat in order to melt the thick steel. I got some good welds on the outside, but the inside welds are ugly and hard to hit. It makes me wish I had a wire feed MIG welder for quick and dirty stuff like this. I vastly underestimated the time it would take to weld the brackets ,and it took me several evenings of work, and almost an entire Saturday to finish most of them.

Here’s a shot of the lower knee braces. I intended to have the hole for the 3/4” bolt to be at the bottom of the brace (more on that later). You can also see the small 1.5” square tubing spacer that I used when welding and drilling:

For fun, I used the mill to square off the 45 degree angles. It would have been faster to just do it with a file, but the mill makes cleaner and more precise cuts.

For drilling, I used my drill press and a bunch of the T2 tapered drill bits I got with my lathe:

I really need to learn how to sharpen drill bits. I tend to just destroy the tips. I did use cutting fluid while drilling, and drilled out the sizes a few times when working up to 3/4” inches. The brackets will hang off the tree with a single 3/4” lag bolt (more details on that later — I had trouble finding the right ones). The wooden 2×8 knee brace will attach to the bracket with two 5/8” bolts. It’ll be solid (or, so I hope).

I decided to redo my wedding treehouse concept. I wanted something far enough out in front of the trees to suffice as a proper area to stand for the ceremony, and the typical umbrella treehouse design seemed like a good idea, so I went with it. This design can be seen in some old treehouse books, such as Nelson’s “Home Tree Home” (the basic treehouse building bible — I used it when I built my last big treehouse about 10 years ago).

I’m opting for a half-round treehouse for several reasons:

1. Cost/wood — a lot of the wood I’m using is reclaimed from when my deck was built (they are 2×8’s used to form the cement retaining wall)

2. Time. I want to get it done sooner than later.

3. I don’t want to kill the tree. The diameter isn’t that large, and I’m afraid that sticking a ton of lag bolts into the tree will kill it if I go entirely around the tree. Even with lag bolts half way around the tree could potentially get damaged, but, I don’t think anything will happen since redwoods are *very* resilient. These redwoods have survived a fire that happened a long time ago (at least over 35 years ago, since the main house has been there that long. )

I’m a little late at writing my blog entry..since I’ve already got a start on the treehouse, but the next steps were to fabricate the treehouse brackets. That’ll be the next entry..

I would like to give a big thanks to Dan Wright, from Tree Top Builders out in PA. Dan has been building some amazing treehouses for quite some time and is well experienced in the art of treehouse building. He offered to talk to me a bit about my new “wedding treehouse” design and gave me some great feedback for how I could improve it. He quickly pointed out how my lower-horizontal brace would easily be over-stressed by the knee braces, and it would need to be really beefy wood (or made of steel) in order to withstand the forces exerted on it. I had not thought of this and he had a great point! I’m definitely more of a a software engineer than an architect, and I wish I had more formal training in architecture and engineering. Dan suggested using several knee braces coming out from the tree, and some other things that got me re-thinking about my design. In the end, I decided to scratch my two-tree approach, and design a single-tree knee brace version using custom brackets. The more I thought about the two-tree approach, the more I realized it would simply pull apart like my old treehouse eventually did. I didn’t want to make the same mistakes (instead, I want to make new ones).

When I built my first few treehouses, I didn’t have the option of using steel brackets attached to the tree. The cost (and hassle) of getting them made wasn’t worth it. Plus, I really enjoy doing stuff myself. Learning how to weld has opened up a lot of new ideas and possibilities for me, and I figured some treehouse brackets would be something within my skill set. I’ll post more details later as my new treehouse progresses.

It is quite cool that people can make a living out of building treehouses, and in many way I envy Dan for building treehouses all day long. But, don’t get me wrong; I really love my job at Apple and working on Cocoa is highly rewarding. Dan has a ton of treehouse experience, and I highly recommend anyone who is serious about building a real treehouse to call him (or some other treehouse company) and get them to properly design your treehouse, or even build it for you. They will build it to last!

Here are a few great pictures from Dan that I’d like to share with anyone who happens to read my blog. It is quite interesting how people are now using steel brackets into pipe to hold the lower knee braces; it gives some space to the tree to allow for growth.