Don’t have a lathe?

Don’t fret. Here is a reasonably easy why to turn a table leg so it has a rounded end. Then you won’t be forcing a square peg into a round hole. I’ll also describe how I made a small bedside stand using this method for the legs.

First thing, what dimension is the leg? — Say it’s 1-1/2″ X 1-1/2″ as was mine. The resultant diagonal dimension would be 2.12″ (or 2 and about 1/8 inch). I had already “edged” the corners slightly so my diagonal was just at 2″. I then cut a 12″ section of electrical conduit that had an interior dimension of 2″ (ABS plumbing waste pipe is another option). The leg was then inserted within the conduit, with thin cardboard pieces placed on the leg corners to wedge it in snug. These photos were taken later, but shows the step I’m describing.

The table saw fence is positioned such that the distant side of the blade would just slice at the point that is the longest length of the leg which would touch the underside of the table top piece.

The blade has been set to the height that would allow the blade to just touch the flat sides of the leg surface of it’s four sides. The leg is 1-1/2″ so my rounding will make the end that dimension. The blade could be adjusted to any height to get a smaller rounded end. The leg-in-conduit is then run back and forth over the blade. The corners are carved down first. The leg-in-conduit can then be slid side to side over the highest portion of the blade. Believe it or not, this method took about the same amount of time as setting up and dealing with a lathe.

The next step is to cut the shoulders of the square to round on the legs. When cleaned up the round surfaces can be rasped/filed to smooth them.

I checked my dimensions with a caliper and lastly tested them out in a mock hole before putting all the parts together for a final fit.

Now to the table project. There aren’t any process photos but the instructions are pretty straight-forward. I was building a small bedside stand for Robin. I didn’t plan this out much. Just an idea that followed from a small length/width, but quite thick (3-1/4″) piece of maple. To begin with I had thought the legs would be vertically straight down. But, Robin introduced a problem. She had a basket that held our dog Jeep’s toys that needed to go beneath the stand and between the legs. That meant the legs needed to splay outward going down.

After more or less squaring up and preparing the top, I made the legs as described above. A piece of spalted maple served for them. With the problem of having to put a basket underneath, I decided to just lay the legs (one side) out as if they were attached at the top. My work table has a white surface, so when the legs were laid out with a taper such that the basket (width dimension) could fit between I could mark around them. I measured the bottom (spread) dimension and then traced the edges out to find the taper angle. In this case it was 8 degrees.

Next was making the stretchers (the 4 horizontal pieces that attach the legs) also of maple. The lengths came from my traced drawing. I cut a tenon by running passes on the table saw at each end on both side faces on all of them. Then I drilled out a mortise on the legs to receive the tenon. After some chiseling and hand carving to finish them the stretcher and legs were ready for assembly.

The last major task for assembly was to drill the holes that the leg dowel end would be inserted. The holes had to be drilled at an angle so I had to make a jig of the appropriate angle that could be stable and level across it surface. The legs tapered from the top at 8 degrees at front to back and from side to side. Question: what is the angle that the holes should be drilled? (Answer in an upcoming post. Hint: it’s trigonometry).

After a final sanding, a dark walnut stain was applied and it was ready for a “dry” assembly. Before I put it together I had thought it might be difficult to get the legs into the drilled holes. As it turned out there was sufficient play in the stretchers to legs so that the dowel end went right in. The whole assembly could then be tightened with clamps. The final step then was gluing and assembling. That was done and excess glue was wiped off, job done.

Epilogue: I goofed up the basket height measurement and the basket wouldn’t fit under the stand. I think had I tried to accommodate the extra height the taper of the legs would be too great. Jeep was cool with it. His basket moved to a nearby location.

Thanks for stopping by. Be sure to check out our books about building a yurt or a small cable suspension bridge. The links to purchase are on the introductory page:

Introduction to Wildcat Man

Images, diagrams, and text copyright 2013-2020 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.

DIY Soil Cement Sectional Floor

I read an article about making soil cement decades ago, possibly from an issue of Mother Earth News. I thought I might want to try it someday. The wood-framed panelized yurt that we built recently was the perfect place for the experiment. The idea of a “dirt floor” seemed to go well with the setting and the unique building. Plus, I could form it in twelve sections, just as the yurt is 12-sided.

Note that this is not the commercial soil-cement used by some highway departments, which uses sand and crushed stone with the soil and cement mix, making it basically concrete with soil added. They might use other waste materials as well, such as cinders and fly ash.

Since I had discarded the article, saving only the “recipe,” I did a couple of tests first. The mix ratio from the recipe was different from what I settled on.  The original recipe called for less cement by volume (5:1) and the amount of water was less. The calculated volume of material for one of the 2-1/2 inch thick wedges was 3 cubic feet. This proved to be inaccurate when using our soil. The loose, crumbly clay soil turned out to need four cubic feet to allow for all the air pockets. So, adjustments were made, settling on a mix of four cubic feet of soil to 1 cubic foot of cement for one wedge.

We divided each wedge pour into 1/4 cubic foot of cement to each cubic foot of clay soil, making a total of four pours per wedge. The water mix would be whatever made it workable, but originally was figured to be less than two gallons.

My first test sample, a very small amount comparable to the 4:1 mix with the water equivalent to the original recipe turned out fine in the test, but proved to be way too dry in the first wedge we mixed and poured. So, the amount of water became an evolving test as we mixed and poured the subsequent wedges. Generally, two gallons per mix worked with adjustments made for damp soils or dryer soils. Even though all the soil came from one pile, the moisture content varied.

I made two tests. I painted one of them with concrete stain just to see how we liked that. We didn’t. The natural color was just the look we wanted for the yurt floor.

Materials needed

This is a list of all the materials and tools we can remember using. The amounts of soil, cement and water needed are detailed in the instructions.

Soil

Cement

Water

Vessels for storing sifted soil

Wheelbarrow for mixing

Shovel

Hoe

Small shovel for scooping and cleaning out last bits

Strong bucket

A variety of concrete trowels, i.e. margin, brick, rounded finish, long finish

Tamper

Fence wire

Plastic sheeting

Tape

Wood and hardware for forms

Step 1 Build the Form

The first step was to make forms. My plan was to pour the wedges from the back of the yurt to the front, every other one. The forms were simply screwed to the yurt deck. They could be easily moved for each subsequent pour. Once six were done and cured enough, then we’d just fill in the final six wedges. The middle was left to put in something fun for a center focal point.

The center was six-sided while the yurt was 12-sided. Due to this, the forms would meet at a corner point, and the center of one of the six sides, thus being different lengths and angles. I made each a little short and used wedge shims to bring them tight. This also made it easier to remove when the pour was cured.

This photo shows how the pours progressed and the form material was moved.

You could use this form system to pour a square or rectangular form by deciding how large a pour you wanted to do for each section.

Step 2 Bring in the Dirt

I brought in what I estimated to be more than enough sandy clay soil for the project, about 2-1/2 cubic yards. I dug it up on our property, but dirt can be found where excavation projects are going on. Just about any kind of earth can be used, as long as it contains clay and sand. It should be free of organic material and debris.

I tested my soil by filling a jar half full of sifted earth and adding an equal amount of water. I covered the jar and shook it for a few minutes then allowed it to stand undisturbed for an hour or so. Once settled, the soil will have separated into layers of sand on the bottom, clay in the middle and silt on the top. The ideal mix is when there is about 75% sand and 15-20% clay. I did several tests and got different results each time. In this photo there is about 50% sand and 50% clay and silt.

Step 3 Sift It, Sift It Good

Once we carved some time between other summer/early fall projects, Robin started sifting. She started by just chopping at the dirt with a hoe, but then figured out one of her plastic greenhouse trays would do the job and give us a more consistent product. After the first pour, we determined that each wedge would require almost 4 cubic feet of dirt. I had built a 12x12x12 inch (a cubic foot) box to measure the volumes. Robin got the four batches ready in advance of each pour by just filling the box with sifted dirt and storing in various holding containers.

Step 4 Mix It Up

The soil went into the wheelbarrow first, then the cement was added in furrows I made in the soil. I mixed that up using a hoe, chopping at it about 2 inches at a time from front to back so that the cement was well dispersed throughout the soil. Dry mixing continued until I couldn’t see any “orange” clay or “grey” cement bits.

Then I added two gallons of water and mixed until we had a batch that wasn’t soupy, but not too dry. We found that the wetter the mix, the better.

Step 5 Get Down and Get Dirty

Since the yurt has a few steps up to it and neither of us have terrific knees, Robin filled the bucket with about three shovel scoops and hauled it up to me inside the yurt. I slopped down the glop and handed back the bucket. One wedge, which was four batches of mix, took about two hours including a break after the wire reinforcement was tamped in after the second pour.

Since we’d have four pours for one wedge, I worked from the back to the front. After two pours, I spread it all out evenly, using a brick trowel to move big blops around and a margin trowel to semi-smooth it all.

Step 6 Start Spreading the Mud

Even though we used the same proportions of dirt, cement, and water for each pour, the consistency varied wildly. After the first couple of wedges, we decided we liked the wetter consistency and I started adjusting the amount of water depending on what happened with the mix. The wetter blend, about the consistency of Sloppy Joe mix, was easier to shovel and work with, plus those wedges were not as prone to cracking, which did happen on several early pours.

Step 7 Add Wire Reinforcement

I had no idea if soil cement cracks the way concrete can, but I figured reinforcement would help by containing the separation if it did occur, holding all snug together. I made a jig to simplify cutting the reinforcement wire, cut 2×4 grid fence wire in three pieces (this made the best use of the material), positioned it carefully, then tamped it into place. It was tamped to get any high ends down and to embed it into the first layer.

I made my tamper from a short approximately 8 inch piece of cedar tree trunk, a hole drilled in it to accommodate a broom handle.

Step 8 Get Back to the Dirt at Hand

While I tamped, Robin loaded the next cubic foot of dirt into the mixing wheelbarrow and measured out the cement. If she had the energy, she also started sifting dirt for the next wedge. We scheduled two wedges a week, weather permitting. We got behind when wildfires in Oregon caused our air quality to become unsafe for breathing, but after a couple of weeks we were able to return to the task. We got rained out a few times as well.

Step 9 Screed It!

Once we poured the fourth batch into a wedge, it was time to screed. I screeded using a 1×3, just as I would for traditional concrete. The “sawing” motion while advancing the screen board forward used in working concrete didn’t work very well. When screeding the soil cement, I found that it didn’t pull along like a concrete mix does. It tended to suck the “mud” from behind, pulling it away from the forms and scraping the surface off behind. The “mud” also built up in front, making it difficult to move it forward. I worked out a method using a margin trowel to remove the material from in front without taking too much.

Step 10 Finish It!

When I got it fairly close, I used a finishing trowels to begin smoothing it out. When working it you can get the surface to pull along to lower areas. Occasionally, air bubbles would develop, and I just punctured them and filled with a little excess mud. When I had it acceptably flat, I used a concrete finish towel to get it smooth. It can be worked to a very smooth surface, but I didn’t attempt to do that.

For the areas between the formed wedges, I taped plastic sheeting to the wedges on either side to keep the mud from adhering to the finished wedges and to keep them clean.

Step 11 Do Something With the Leftovers!

Four cubic feet was just a little more than we needed, so we used metal flashing and clamps to make forms for stepping stones. We added leaves to give them a fun look. I have no idea how they will hold up in the rain and freeze, but I guess we’ll find out!

Sections are still curing, but we might have a pinwheel effect going on here!

In conclusion, a crew of two old fahts did take a few weeks to accomplish soil cementing a 200 square foot area, but it’s a unique and durable floor. Plus it adds mass to the building to help maintain a comfortable temperature inside. I’m working on my middle piece now and will post an update when it’s done!

If you’re interested in how I built the rest of the yurt, we published a book. Here are the links:

Building a Wood-Framed Panelized Yurt, in color

Building a Wood-Framed Panelized Yurt, black & white

Text and photos on this blog are copyright ©2020 by Marvin Denmark and Robin Koontz. As much as we love to share, please ask permission before re-posting. Thank you!

Restoring a Funky Dump Chair

I wouldn’t ordinarily write about repairing a chair, but I wanted to pay tribute to the artist who created this chair. The exact details of how this chair came into my hands isn’t exactly clear now. It seems that in the era around 1978-1979, while taking garbage to the Glenwood dump near Springfield, Oregon, I spotted a funky little chair. It had been left by someone by the side. I was attracted to it’s unusual design. Obviously it had been hand-made, a one of a kind. So I loaded up my “dump-dive” find and headed home.

It was carried from our Springfield house to the new house we built. tucked away here or there and finally in my shop for all these years, it was my intention to restore it some day. That day finally came while I was looking for projects to do while taking a break from other projects. By then the chair had lost a loose piece off the back and had gathered a lot of dust and debris.

Inset

This is the chair with the dowels covering the (leg) screws chipped out. Inset gives the chair dimensions. A few words about it’s condition and construction. It seemed to have been immersed in a creek or body of water at some time. There was a fine layer of silt beneath the joints at the back to seat connection and beneath the seat to the legs. It was constructed of redwood. The seat was connected to the legs using brass screws with a dowel cap over them. Everywhere else common nails were used to connect the parts. I will point out other details through the pictures.

The disassembly.

IMG-1536

The legs laid out next to the cross tie piece.

The seat was attached to the legs with 2 1/2” slot head brass screws. Two through the seat to each leg and an additional one screw into the tie piece.

IMG-1532

The legs were connected to the tie with a pair of 7 penny common nails angled in through the leg tops into the tie, each side.

IMG_8353

You can see where the artist had considered using dowels to connect the legs to the seat. (Note the four holes at the tops of the legs).

IMG_8352

I’m set to reassemble the seat to the legs. The seat has been attached to the back. I used 3” ceramic coated deck screws, with Phillips head. The legs are connected to the tie using a 2” same kind screw.

IMG_8355

The chair back has a support brace at the bottom attached to the back with the 3” screw, previously attached with a 16 penny common nail. At the bottom right you can see a patch I made to fill where I lost the original broken piece.

IMG_8436

Here is the restored chair beside our front door, where it will live out its useful life. We have speculated on the chair’s purpose. It has the characteristics of a spinner’s chair. But Robin has proposed that it may also have been a musician’s chair, as in a cellist.

IMG_8439

The artist probably left his calling card on the chair. Under side of the seat and up front is a routed out image. On the right side you can see a crack. The seat was split full length . I repaired it by cutting a slot and gluing in a spline to hold it together along with the glue.

A google image search (now, but not when we acquired the chair) pops up the Gasoline Alley character Wally Wallet. Robin thinks Skeeziks, but I haven’t found an “aged” image of him. In any case, was the artist presenting himself in that carving? We will probably never know… unless someone close to the artist reads this blog.

May the yurt surround you.


 

Thanks for stopping by. Be sure to check out our books about building a yurt or a small cable suspension bridge. The links to purchase are on the introductory page:

Introduction to Wildcat Man

Images, diagrams, and text copyright 2013-2020 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.

Building Free-Standing Stairs

In February 2019, our 80’ long suspension bridge took a big hit due to an ice-snow storm. An old maple tree above it snapped and came straight for one of the support posts, taking a few trees along with it. The post snapped about in half and the bridge went sideways. The sad event is chronicled here.

The good news was that all the cables and the cable-locking system components were not affected at all. The eye bolt on the broken post that holds the main cable was bent and that was about it for damage other than the post! After a whole lot of cleaning up of debris, my neighbor and I, with some help from the photographer, installed a new (used) power pole and lifted the bridge back up.

The free-standing stairs on either side of the bridge were constructed of recycled materials way back in 2005 and the decking was not meant to be permanent either, so this disaster gave us an important reminder that we needed to do some updating on our bridge.

89078922_2882351408499087_5029192406222766080_o

The decking is ready to install later in the summer and meanwhile I screwed down planks to keep the bridge safe to walk on for now. The free-standing stairs became more of a priority because they were already falling apart before the storm.

Here are some instructions that assume you have some carpentry experience. Feel free to email me if you don’t understand something.

Pieces Needed (lengths depending on the rise and run of your stairs):
2 – 4×12 pressure-treated beams (stringers)
4 – 2×4 pressure-treated lumber
5 – 2×12 pressure-treated lumber for the steps

RiseTread

Two rules of thumb for free-standing stairs:
1. One riser plus one tread = approx. 18 inches
2. Two treads plus one riser = approx. 28-29 inches
There are other rules of thumb, such as when dealing with landscaping and low slope terrain, but these two rules will handle almost any building situation.

 

Stairs

When you design your free-standing stairs, you begin with “What is my total rise?” Take that total rise and see how a 7” rise and an 11” run will work (which is the recommended ratio). Divide 7 into your total rise. That will indicate the number of steps (including the landing). My stairs have a 7” riser and 11” tread measured nose-to-nose with a 35″ total rise with a 32-1/2° incline. What if you have a total rise not divisible evenly by 7? Perhaps it’s 34”. 34 ÷ 7 = 4.85. Round 4.85 up to 5. 34 ÷ 5 = 6.8 or 6-25/32 or 6-13/16. With that number, you would just leave the tread at 11”.

If it turns out that you have a total rise that is more evenly divisible by the next higher riser, say 8”, go with that. For example, a 32” rise would give you four 8” steps with a 10” tread (remember the rule of thumb).

Not to belabor this, but you could have a rise of 7-1/2” if it divided into your total rise evenly. And then the tread would be… (you figure it out using the rule of thumb*).

The other question is, “How much space in front of my stairs do I have to work with?” If you are in tight quarters and the rise would end up being more than is comfortable for walking, then you’ll make a landing and turn the stairs at an angle to gain more run that gets you to your final landing. You can also build an alternating-tread ladder stair. I built one and will blog about it soon but I think there are instructions for it online.

Process: The layout is carefully marked on the two 4×12 pressure treated beams (stringers), and cut. The steps will fit into slots in the beams and screwed from the sides. My slots are 3/4” deep.

1

To carve a slot, I use my skilsaw to cut multiple passes, then chisel out. It’s easy to knock out the remaining wood after cutting. The very back where the round blade doesn’t reach needs extra work.

2

Pre-drill the holes for the screws.

Each beam is attached to a vertical 2×4 pressure-treated piece, based upon your total rise. Also, each beam has a horizontal pressure-treated piece based on your total run. I used a wood preservative in the slots to give them extra protection from rot.

7

For the near-stairs, I screwed in the steps and hauled the assembly to the bridge site.

9

For the far-stairs, I assembled the components on-site.

* 10-1/2”

Thanks for stopping by. Be sure to check out our book about building this strong bridge. Here is the link:

Building a Small Cable Suspension Bridge with the Cable Locking System

Images, diagrams, and text copyright 2013-2020 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.

Hoisting a Suspension Bridge to its New Post

This was the next part of the repair process. Once the post was installed, gravel was shoveled in and tamped. The official tamper tool was too big at first so a 2×4 worked. Next they hooked up the cable to the dead-man and tightened the turnbuckle, which will be adjusted again later. Then it was time for a beer! The hard part was over.

P1020049

Now it was time to hoist the bridge. They used the come-along again, which worked okay but seemed like it needed help. It took a bit of regrouping, but finally they added a cable winch so there were two devices working instead of one. It took time, but the 80′ bridge was eventually hoisted! All pictured here happened in about 5 hours, including beer breaks.

BridgeUp

BridgeUp2She’s a little beat up and broken, but at least she’s up!

CheeseThe obligatory cheesy grin, photo compliments of the amazing Keith Grossman!

KeithIsFirstWe cleaned off the leaves and the boys crossed the bridge, Keith first. The decking is pretty badly damaged but it was okay for now. Nice not to have to walk across that creek again this winter, assuming the bridge stays out of trouble. Here’s to hope!

Next, Marvin will be straightening things out and making it a little safer for crossing. We’ll replace all the decking as time and weather allows.

Thanks for stopping by. Check out the movie on our Facebook page! And, be sure to check out our book about building this strong bridge. Here is the link:

Building a Small Cable Suspension Bridge with the Cable Locking System

Images, diagrams, and text copyright 2013-2019 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.

Replacing the Post on a Small Cable Suspension Bridge

P1020046100_8407

P1020059

As you might remember, February 25, 2019 was a bad day for our 80′ suspension bridge that we built in 2005. Part of a large maple tree weighted down from heavy snow decided to break and fall directly on one of the support posts on the other side of the creek, bringing lots of other trees with it. Once it thawed and we could get someone over to clean up the mess, we assessed the damage. We had to replace the post, which involved many steps, and most of the decking. Also, we had to raise the bridge again.

We lined up a contractor and a crew to do the work with Marvin’s supervision, but they were busy and having a hard time fitting us in. Summer came and went, and when the rains started this fall, we decided we could do it ourselves with help from our neighbor (and plenty of beer!). We are not as young as we were when we built this bridge, but we still have the same determination to get the job done. To note, since the damage is on the other side of the creek, everything had to be done by human power and ingenuity. And did I mention plenty of beer? I think I did.

Beers

dig it

 

DigItTools

One of the first tasks was to dig up the old post. All went well until we realized it was buried 4′ deep, not 3′. We should have read our book! The last foot or so needed a special tool since there was no room for a shovel. The cut cake pan worked the best. Cut the pan and then screw the two halves together and we had a quick and easy gravel scoop!

CutNewPostCarvePostEnd

We used a power pole again, though this one is pretty substantial. The end was carved for the metal collar that connects to the bridge cable and to the cable to the dead man. Holes were drilled and the raw end was treated with preservative.

BangingCollar

Marvin had to chisel the collar off the old post, then he replaced both eye bolts, which were bent when the trees hit the post. The eye bolt for the bridge cable is 3/4″ and the one for the dead man cable is 5/8″.

The above collection of photos shows some of the post-wrangling. The two guys used a pee-vee, cables, chains, and a handy little tractor on the opposite side to get the post across the 40 foot wide creek with steep banks on both sides. There’s a movie of some of this on our Facebook page, link below. If you wonder why a lot of cable is wrapped up on the tractor bucket, that’s because we had to reel it in as the post headed across the creek.

PostReadyAndTripodTripodPulley

Next, the boys built a tripod using 20′ 2x4s and installed a pulley at the top. At first they had rope to pull up the post, but it was soon replaced with cable because the post was heavier than estimated.

They used a come-along which worked to get the post raised so much, then the post had to be secured, the rope loosened, and the come-along reset. It took several resets before the post finally drifted above the hole.

InPost

 

TargetAim

The last trick was to center the post on the pin in the concrete pad as it was lowered into the 4′ deep hole.

PostIn

The new post is in place!

BridgeSpanWithNewPostIt was cool to see the new post up and almost ready for the bridge deck. Next, we back-fill with gravel (by hand of course) and tamp it in. Stay tuned, and be sure to watch for exciting movies on our Facebook Page here!

Thanks for stopping by. Be sure to check out our book about building this bridge. Here is the link:

Building a Small Cable Suspension Bridge with the Cable Locking System

Images, diagrams, and text copyright 2013-2019 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.

Scaling Up the Size of the Yurt – the Beams

Let’s consider the beams for the 20 foot yurt. For the book I used a 4.5/12 slope and for practical reasons I would use it for your project. I’ve walked on many different sloped roofs and on some that couldn’t be walked on without ropes. I can say that you can comfortably walk or work on a roof that is a 4.5/12 slope.

Pic1

One thing that you may not immediately notice is that I assign the slope to the beam and not the roof plane. Why do that? If you use the roof plane you subsequently have to calculate the “hip” (that joint that joins the adjacent abutting planes) of the roof structure; i.e. directly over where the beams run. Why make things more complicated? Because the beam’s lengths are determined using a slope calculation, it simplifies your calculations. So now to that calculation.

When you solve for the hypotenuse of your 4.5/12 slope (triangle) you have a 4.5” leg perpendicular to a 12” base leg (level). Both squared (20.25+ 144) gives you 164.25 and the square root of that is 12.816 (your hypotenuse). How does all of this relate to the beam? Two things: first for every foot on the level that the beam travels the beam rises by 4 1/2 inches (so for a theoretical beam of 10 feet the “up” end is 45 inches higher) and second, for every foot traveled horizontally (on the level) the beam’s length increases by X 1.068 (so in our 10 feet run the beam grows to (10 X 1.068) or 10.68’ which is just over 10’-8”.

Pic3
So to complete the beam length calculations you have to subtract the skylight ring assembly and add the overhang you want (here beams are assumed to go all the way to the center of the yurt). Both of these are accomplished in the same manner as above.

Pic5

For the skylight, take the diagonal of the framing of the skylight ring (a level measurement from one corner to the opposite corner) and then halve that. That is then taken from the beam overall length, after calculating the “sloping” length.

The overhang is a bit different. To make it simple just consider the overhang equal to whatever you extend the beam tail (whatever is hanging past the walls). So, if you wanted a two foot overhang, just extend the beam out two feet (using the slope calculation, of course). This will be close enough for a two foot overhang.
Pic4

Pic2Otherwise, if you want a more precise dimension for your overhang you will need to do some more calculations. This requires a bit of trigonometry. It goes like this: Say you want a two foot overhang. This is a two foot projection that is horizontal (level) from the wall and parallel to the wall. Since we know the number of sides we have, we get the number of divisions in the 360 degree circle. That gives us the peak angle for our triangle. We will use 1/2 of that angle (see drawing below). Our long side of the triangle is 2’ (our overhang). So solving for the hypotenuse: recalling our trig formulas: CAH — cosine of the angle = adjacent side divided by the hypotenuse. Solving for H we divided through by A to get H=C/A. Now do the “rise” calculation from above to get the actual beam overhang length. This sounds like a lot of work, but honestly, it’s easier than reading this entire article!

Be sure to get a copy of the book which explains the rest of building a wood-framed panelized yurt. It’s available on Amazon in color paperback, color ebook, and b&w paperback. And hey, if you build a yurt after reading our book, please send photos to share, thanks!

Here are the links to purchase the book:

Building a Wood-Framed Panelized Yurt, in color

Building a Wood-Framed Panelized Yurt, black & white

YurtBookCover-w-Template-FINAL-COLOR

Suspension Bridge VS Big Tree: Bridge Wins!

February 25, 2019 was not a good day for our suspension bridge. A snowstorm hit that weekend with 8-12 inches of wet, heavy snow, and trees started falling everywhere. Power was out all over the state, including here (which isn’t that unusual given our rural location). But alas, one big alder tree snapped and landed on one of the bridge posts, breaking it in half. Here’s what we were faced with when we cleared out the mess on the our side:

BridgeNorth

The cable-locking system held up as did all the stringers. We can’t see the other end of the main cable but assume it is also okay. Just nothing there to hold it up anymore!

BridgeDamage1

Since the creek is still too high/freezing cold to cross, we can’t easily assess all the damage. But the bridge is “hanging in there” until help can arrive. Hopefully our spring won’t need any maintenance in the meantime.

Once we cut away the mess, we’ll need to dig out the old post (three feet), get another post across the creek and in place, tamped in with gravel, and then all the hardware re-attached. The decking will have to be removed so the structure can be lifted up more easily. As for the dead man, we’ll have to find out how it fared the blow.

BridgeDamage2

You can see the tree that did the deed just uphill from the bridge. Nice aim, tree!

BridgeDamage3

Ah well, it was time to replace the decking anyway. We’re looking for metal paneling of some kind (that we can afford). I’ll post photos of the fix later in the spring! Onward. P.S.: We’re getting too old for this sh*t.

UPDATE: So far we replaced the post, reattached the main cable and cranked the bridge back into place. You can see how those things happened here and here. We also built new new sets of stairs, and how to do that is here and also is a featured Instructable.

Scaling Up the Size of the Yurt

I want to talk about scaling up the size of the yurt. We had considered adding this in the book but decided against it. So I will take you through the process now. The size or diameter of the yurt in the book was 16 feet. Considering the next reasonable size up one might think of a 20-foot diameter. Let’s follow the steps to creating it. The parts that get affected are the foundation, floor panels, wall panels (though not height), beam length, roof panels, and possibly the skylight (size). If you follow this process you can create a yurt of any size (within reason, as loads on the beams become a factor). We begin with the floor plan, which in turn informs us of what the foundation will be.

With a diameter of 20 feet we are looking for the circumference. That is found with the formula C = d X pi (circumference = diameter X 3.1416). C = 62.83185. With this information we can find the number and width of the wall panels. First, for the number of walls, we divide the circumference by 4. Four feet is the “ideal” working dimension for our walls. When we divide we get 15.7. An uneven number or decimal number doesn’t work well for wall layout. We want an even number of walls, so we round up to 16. Now we divide the circumference by 16 to get walls of approximately 3.927 feet or 3 ft – 11 1/8 in. That’s a good workable number.

chordlengthLet’s step back a second. When we divide the circumference of a circle by assigning a number of sides to it not only do we get our floor panel angles at the peak and the base (more on that shortly) but we also get a dimension that makes for an approximate length for the base of the triangle, which will be our wall length. But this dimension is not the true base of the triangle. To get that you would have to use the chord length formula. There are variations on that formula depending on the conditions known. For us it is the simple one: 2 r sin (angle)/2. We have a radius of 10 feet and an angle of 22.5 degrees. 2 (10) sin 11.25 degrees = 3.9018′, or 3 feet – 10-13/16 inches. This is our most correct length for the base of our triangle and the width of our walls.

Print

The next step is to find the angles involved in making the various panels. We now have 16 sides around this yurt. In recalling our math classes we know there are 360 degrees in a circle. Dividing 360 by 16 will give us 22 1/2 degrees for the peak angle. The sum of the interior angles of a triangle is 180 degrees so that leaves us 157.5 degrees for the base angles. Since the sides are equal, than the angles are equal at 78.75 degrees. Remember, the peak angle for our yurt in the book had 12 sides and thus (360 divided by 12) 30 degrees with base angles of 75 degrees each. Some people may not like dealing with partial angles, seeking more simplicity in their work. So let’s look at this yurt with more sides, but same diameter, say 18. That would give us angles at the peak of 20 degrees and at the base 80 degrees. Using the chord formula above the wall length will be around 3.49 feet long. That will waste about 6 inches of siding plywood for each wall but is still a workable width.

With the information above we can layout the foundation, and we could finalize the math to build the floor panels. We can build the walls also. If we follow the process in the book you will see that not much changes except for the length of floor joists and later the roof framing members. Walls will stay the same height so just a width adjustment is necessary. I should say at this point that you could make the walls taller to any height chosen, which will only effect a later calculation for the placement for the skylight ring and it’s tower height. So feel free to experiment!

Following this information and combining it with what is in the book you should be able to design your own yurt of practically any size. Just remember the larger you go the more need for paying attention to the loads placed on various members.

Next time I will talk about the beams, tower and skylight, and roof panels for a larger yurt.

YurtBookCover-w-Template-FINAL-COLOR

Here are the links to purchase the book:

Building a Wood-Framed Panelized Yurt, in color

Building a Wood-Framed Panelized Yurt, black & white

Book-inspired Suspension Bridge in Virginia

We were delighted to finally receive photos of a suspension bridge that was inspired by our book, Building a Small Cable Suspension Bridge With the Cable Locking System.

1-7

According to the builder, Mo Goldman, the bridge is just under 40′ feet in length and 4′ wide (basically half the length of our bridge) and is located in Virginia just outside of Charlottesville.

1-5

The posts are aluminum, 13′ in length, 6″ round with 1/4″ thick side walls, easy for two guys to carry. The post holes are 3′ deep and about 2′ around; the posts are placed on a concrete footer prior to pouring around them. Everything was hand-dug and poured because they were limited to access with a Polaris on one side.

It was fun to see that Mo set up a temporary cable to move materials across. That’s how we moved our gravel for the opposite side, one bucket at a time. But Mo took it further and carried the posts, other materials, plus wheelbarrow and even himself across their “zip line.”

SetUpStringers

Mo also followed the idea of setting up the catenary curve between two trees/structures located away from the creek to plan and build the cables and stringers on dry ground.

MoGoldman

Mo didn’t use our cable-locking system, but instead used a system often used for this type bridge – an appropriate length “eye” bolt placed in a drilled hole in the beam. The suspenders were then connected with a chain connecting link, which uses a threaded portion mating to a free spinning nut to open or close it.

He wrote to us about the bounce in his bridge which was more than he expected, though not a big deal. I noticed that he paid attention to harmonic resonance in the arrangement of the stringers so they were assumed off the “nodes,” so wondered if the decking material he used could be partly responsible (a suspension bridge is going to bounce, that’s a given). He used a material called Trex, which is a deck material made from recycled plastic and wood fiber. Trex tends to flex more than standard lumber does. We concluded that he needed to stiffen the deck, so now he is working on some ideas.

1-8

Mo even put up a sign on his bridge similar to ours and inspired us to remake our sign so that it names the creek, too. We hope others who build a bridge based on what we did will also send us photos and notes about their building experience.

Meanwhile our book is available in paperback and as an ebook via Amazon.com.