Futon Frame Finalized

For the past few weeks I've been narrowing in on my design for the futon frame using Google Sketchup. I know I'm starting to sound like a fanboy for this program, but it's hard not to be impressed with how simple it makes 3D modeling. That's good because I'm no engineer :)

I've wanted to go the direction of sliding the seat section to cause the seat back section to rise, but I needed to figure out the right linkage, and it came down to creating 5 'scenes' in the model, where the seat back would pivot 14 degrees between each scene (for a total of 70 degrees, the ideal angle for a seat back measured from the rear). If the seat section were not to slide backward, then the pivot point on the seat back would have to be a groove with a slight arc to it. But, in having the seat slide, the model shows that the seat back pivot point can indeed be a fixed point. So a carriage bolt could serve to connect the seat back section to the riser arms. Drilling holes is much easier than machining grooves!

Here are the 'up' and 'down' pictures showing the top/front of the frame:

Notice I've updated the model to show the 1 X 6's previously added. As the seat back section is lowered, the seat section slides to the edge of the support rails.

Below are shots from the underside, showing off the linkage:

I've added the 1 X 4 runner stiffeners to both sections, the seat back cross-braces that the riser arms connect to, bolt positions, and the rear connection points for the riser arms. My thought is a 1 inch steel pipe, maybe EMT, that passes through the riser arms on both sides. Construction adhesives and a couple screws should hold each in place. The outboard sections of the pipe would be held to the underside of the support rails with some pipe brackets, and allowed to pivot freely inside the brackets. I'm thinking of first mounting the pipe brackets to a pair of L-brackets, making it easier to attach them to the rails - from the sides instead of from underneath. 

As you can see, having the pivot point underneath provides some tilt to the riser arms. What I don't know is how much force will be needed to push the seat section to get the seat back to rise, but it will definitely need the pivot point to be below the plane of movement to 'kick up' the seat back.

If all goes well this weekend, the next post should have more than just illustrations to show!

Floor Is Done

This weekend was all about finishing the floor. Nothing too fancy. Just a good sanding and cleaning, followed by four coats of polyurethane, with a light sanding of 320 grit paper after coats 3 and 4.The poly really popped the colors and grains out of the wood. I am glad I didn't stain it. It's now a proper floor ...

Fabbing a Futon Frame

Given I needed to take Friday morning off to meet with Nate's teacher, I decided to take a vacation day and put some effort towards the futon frame. I had worked up some plans prior to the trailer being built, as I had to have a general idea of how I wanted it laid out. Here's a picture of what I originally had in mind (designed in Google Sketchup) ...

The original idea called for two sections of equal size, supported by 2 X 4's attached to either side of the trailer. Each side would have two each. Those are the white sections underneath the frame. They were installed by the builder and will bear the load of the futon and its occupants. I also had a plan to include a couple of gas lifts - the black cylinders shown above - but I'm moving away from that idea due to the cost and complexity of trying to figure out how big they need to be, and where to mount them. Instead, I'm thinking of using a set of support bars with pivot points both on what will be the 'seatback' section, and on the 2 X 4 supports. When the 'seat' section is slid back towards the rear on the support rails, the support bars will pivot the seatback upward. I just have to figure out the mechanics of it, and hopefully it will be as simple as I'm imaging it to be.

Originally I had planned on using hardwoods, like red or white oak. These are preferred in furniture making due to their strength, and given the floors are oak I thought it would compliment well. But the cost for the materials is high (about $2.50 a linear foot). I decided that Southern Yellow Pine would be okay. Given the frame is going to be covered by a futon, appearances weren't as important as price. SYP is strong enough to work, and about one fifth the cost.

I picked up some 1 X 4s and started to work. Most of Friday afternoon was spent cutting up the lumber. I planned to use dowels and glue to attach the slats to the runners, but it was probably a good thing that the doweling jig wasn't working out. I picked one up at Harbor Freight for about 10 bucks with the intent on using it for the frame. The reviews said that once you aligned it, it would position the drill bit exactly in the middle. I tried many times to get it to center, but it just ended up setting both holes equally off center. When I dry fit the pieces, the slats had a twist to them. It took an hour or so to make all those holes, so I was pretty disappointed with the result. I figured I'd sleep on in and hopefully come up with another idea in the morning.

Which I did. Saturday morning as I was lying there in bed, I thought that if I attached a couple 1 X 6's underneath, it would provide a 'shelf' to which I could glue and screw the slats to. Not only would that be a stronger connection, it would make for a much stronger overall frame. The runners are transferring all the load to the sides, and if I stuck with 1 X 4s I doubt the structure would have been strong enough.

Here's a shot of the first section clamped and glued. 1 X 4's only, runners and end pieces ...

I continued working Saturday and Sunday (amongst my usual weekend chores, errands and a birthday party), and completed assembly of the two sections. I slid them into the trailer to test their fit. My measurements appeared to be correct - when I lift the 'seatback' section, it has enough clearance to get by the side windows without bumping the window frames. There aren't any hinges on them yet, but you can picture where they will go ...

I sat down in the center on the front section, and noticed a slight spring and give under load, but they appear to be very stout. Each section weighs just under 40 pounds. The futon should help to distribute the weight a little - just need to be careful not to center too much weight in the middle.

Next weekend I'll switch my attention to finishing the floor and adding some molding to the sides.

UPDATE 10/22: I played around with Sketchup some more, and modified the model so that it includes the seatback lift mechanism. The animation is a bit rough, given it works from the first and last position only, so forgive the in-between movements not being well aligned. But it's enough to evaluate the mechanics of it ...

I'm also going to go with some advice from my Dad and add a single, vertical 1 X 4 as a stiffener to each of the sections. As sturdy as it is, there still needs to be a member to help carry the load tangential to the grain. He suggested a placement under the slats, so I may end up with something like this ...

This will work for the seat section, but the seatback may need something a little different. I won't be able to go all the way across, due to needing clearance for the riser arms. I'm thinking a shorter span with a couple short, vertical pieces perpendicular to the span on either end. Kind of like an 'I' shape with the short lengths parallel to the slats just inboard of the ends. These could also serve as joints for the riser arms.

Floor Is In!

Notwithstanding low light and lack of a decent still camera, I am still happy to share with you a few photos of the Compass Rose's new red oak floor (even if it's a bit blurry).

Next up ... sanding, staining and finishing with poly.

Here comes the floor!

So thanks to Nate my day started at about 5:30am, and as I was to find out later in the day, it might have been better for the both of us if the little guy had slept in some more. But as we were up with the crack of dawn, we ran and got some coffee and doughnuts (chocolate milk for Nate), then came back to the house were I jumped right into the task of laying hardwood floors in the teardrop.

As I mentioned in the last post, I decided to go with 'utility' hardwood flooring. It's solid red oak, but with 'utility' grade you get a mixed bag of cuts - everything from broken pieces, cross grain cuts, knots, odd coloring and just about everything you could think of that would cause a board to get kicked out by those quality inspectors. The up side is that it's dirt cheap - about 80 cents a square foot - and for this project I could live with some of the lesser issues. First up was the sorting of the wood.

I built 3 piles - good, okay and, well ... firewood. As the teardrop floorplan would have over half of the flooring covered by either the bunk frame/cabinet or the futon, I'd probably make out okay with the 'okay' wood installed in these areas.

Above is the 'good' pile. I couldn't see much wrong with these. They were mostly short pieces of about 12 inches long, but there were some really nice long pieces in there too.

Here is the 'okay' pile. I found some off color pieces, cross grain cuts, a few small knots and tiny bug holes, and some nice pieces that had rounded cuts at the very ends (figured I could clip off the bad ends).

And last is the firewood pile. Mostly splits and knots and missing tongues/grooves. As expected it was about 20 to 25 percent of the batch. Sorting took some time as I had to sit down and inspect each piece.

Next task was putting in the underlayment. This is a thin foam sheet that's coated on one side with a moisture barrier. The hope is that not only will it smooth out the subfloor, it will also keep any moisture from working its way into the bottom of the hardwoods - unlikely though given the thorough coating of asphalt emulsion on the underside of the subfloor, but better safe than sorry.

As the sun came up, so did the heat and humidity. By the time the underlayment was in - about 9 am in the morning, the temps were already above 80 degrees. With poor air circulation in the garage I was really feeling it, and sweating bullets too.

Now to nail in the hardwood. Given the mishmash of lengths, the picking and mixing of pieces was fairly easy. I ended up only having to trim the final piece of each run, and in most cases the cutoffs were just a few inches. I'm using 1.25" brads in my air nailer. This is probably a little shorter than normal but I didn't want the brads to go all the way through the bottom. And aside from just a few misfires, they appear to be holding well. I'm nailing perpendicular to the top faces along the walls, and at roughly a 45 degree angle back into the tongue edges. It took a couple rows to get a good feel for how high up on the tongue I should fire in the brad - and had to go back and use a nail set on a bunch of them. I found that nailing a little lower on the tongue worked better, as the brad would end up setting with a nice countersink, and I could get a better bite on the subfloor. I don't know if this is the best way but as it's working I'm going with it.

Only thing is it's a slow process. By noon I was feeling the onset of heat exhaustion - mostly due to how out of shape I appear to be! I had only gotten about 10 square feet done. My folks were coming down for a visit, so I decided to take a break, get another shower and wait until the evening to resume. After lunch both Nate and I took a nap for a few hours. That helped. By 5pm I was ready to get back into it.

The evening progress seemed quicker. Temps and humidity were less, but I also set a fan in the doorway to help with the circulation. I was also keeping to a better routine with less wasted movement. At 8:30pm I hit my midway mark on the floor and called it a night ...

The pieces slid in along the walls are to give it the proper spacing for expansion. Walking on it feels solid and level, and I'm no longer hearing the creaking when walking on the subfloor. I think it's going to go in well and so far I'm pleased with the flooring choice.

Tomorrow I hope to finish laying in the other half - we'll see as I really haven't gotten any of the weekend chores done (groan)!